A 20-liter oxygen cylinder can provide more than an hour and a half of air supply at a depth of about ten meters, while the oxygen cylinder that Shi Lei and the others carry can provide about seven hours of air supply.

Moreover, the oxygen mask they use is also a new technological product, even if they don't carry an oxygen cylinder, with this mask alone, they can hold on to a depth of ten to fifteen meters in the sea for more than four hours.

This oxygen mask can extract oxygen from seawater and provide it to divers, and its seawater filtration system is so delicate that even water molecules cannot pass through, only oxygen molecules can enter and exit freely, which achieves the effect of breathing in water like a fish.

The oxygen mask is powered by a tiny plastic battery, which is small enough to last four to five hours of use.

Of course, these are real luxuries, and although such oxygen masks are already available on the market, those civilian products generally only provide a diver with an oxygen supply of about 40 minutes.

The gap between them is by no means something that can be made up by a simple price of five or six times.

The price of an ordinary oxygen mask on the market ranges from more than 1,000 US dollars to 5,000 US dollars, but the oxygen mask used by Shi Lei and his family, which can ensure at least four hours of oxygen supply, costs nearly 100,000 US dollars.

Coupled with that wetsuit, Shi Lei paid more than half a million US dollars for this trip to the island alone.

This does not include the price of replaceable equipment, Shi Lei even prepared a replacement worth 300,000 US dollars, and the 300,000 US dollars in exchange for only a few plastic batteries.

From the high price of this kind of battery, Shi Lei also understands more about the importance of the new energy battery developed by Kong Fandong, which is a battery that can definitely be used for civilian use, and it is a product that can really be mass-produced in the civilian field, rather than this kind of high-end black technology that even he feels a little painful to use.

Including the batteries that can be replaced, the set of equipment on Shi Lei's three can provide them with more than fifteen hours of breathing time at a depth of about ten meters, which should be enough in any way.

After all, they don't stay in the sea water all the time, and with the help of the propulsion device, the actual time they stay in the sea water is four or five hours.

The reason why the equipment has been prepared for such a long time is purely just in case.

Above the sea, there is a calm, undisturbed waves, and only when the sea is slightly undulating and pushed to the seashore can it form waves.

However, at a depth of about ten meters, there were three white lines, and Shi Lei and the three of them were advancing at a very fast speed, steadily approaching the small island.

According to the fishermen's descriptions and records, Shi Lei was already quite familiar with the topography of the island, and their target was an area that was completely unsuitable for boats to dock.

The shore is a rugged reef, and there are all kinds of reefs underwater, no matter how small the boat, just a few hundred meters away from the coast, it will run aground, or even crash directly.

But this is not too much of a problem for the three frogmen.

The three of them cautiously crawled in the water and approached the shore.

After careful observation, the three of them went ashore, and then quickly approached a small cave under a cliff on the shore, following the map drawn for him by the boatmen.

When you get to the bottom of the cliff, you can actually see the appearance of this small island.

On the distant shore, there are a large number of traces of the fishing operations of former fishing boats, and although the wharves and the fish fields enclosed by the sea have long since become dilapidated due to disrepair and unused, you can still see that it was also bustling with people in the past.

The two divers were only responsible for bringing Shi Lei to the island and bringing him back to the starting point when Shi Lei had finished his work on the island, for which Shi Lei paid each of them $100,000. They will not accompany Shi Lei into the depths of the island.

He handed over all the equipment to the two divers, and told them that they would hide in this small cave, and Shi Lei would return here in two days at most.

And if Shi Lei hasn't come back after two days, they can leave on their own.

In the previous box tied to the reef, some food and fresh water were prepared, enough for the two of them to consume here for two days.

After confirming that it was correct, Shi Lei left the cave and walked towards the center of the island.

Luckily, Shi Lei didn't go far when he saw two guards patrolling with guns on their backs above the cave.

Shi Lei hid behind a reef, observing the patrol route of the two men.

The two of them seemed very lazy, probably thinking that it was impossible for anyone to break into this small island, and they had already turned around when they were two or three hundred meters away from Shi Lei.

And Shi Lei is now more than five hundred meters away from the cave.

Even if the guards had patrolled farther away after the shift, they probably wouldn't have discovered the cave, nor the two divers hiding in the cave.

After walking a short distance, Shi Lei saw a lonely person.

The man was wearing a white coat and looked like the staff in charge of the experiment on the island, and this kind of person was naturally Shi Lei's best target.

Quietly approaching the guy, Shi Lei's palm fell, and he easily knocked the person to the ground with one palm.

Then Shi Lei covered his mouth, and the man's pupils showed extreme horror, and he didn't even dare to struggle.

The man was in his thirties, and he still had an ID card on his chest, Shi Lei glanced at it and learned that this person's name was Dickens, which was a very brilliant name.

Shi Lei lowered his voice and said to Dickens in English: "I don't want to kill people, but if you dare to shout loudly, I don't mind killing you." ”

Dickens nodded in horror, indicating that he would never make any sound.

Shi Lei pulled out the dagger in his leg, pressed it against the major artery in Dickens's neck, and slowly let go of his hand.

"Are you a R&D person?" Shi Lei asked in a low voice.

Dickens nodded vigorously, and said in a low voice: "I'm just an ordinary researcher, you must not kill me, I am only here for the high salary given here." ”

"What the hell is this for?"

"Research on small reactors of the palladium element, which can provide a large amount of energy ......"

The dagger in Shi Lei's hand tightened, interrupting his words and saying, "I know what the palladium element can do." Where is your lab?"

Dickens shook his hand and pointed to a small white hut not far away, peeking out of the dense forest.

"Can I get in with this?" Shi Lei pointed to the ID card on Dickens' chest.

Dickens nodded and said, "This is just a card to open the door of the laboratory, there are two guards at the door of the laboratory, if you want to blend in, I'm afraid it's not that easy." ”

"You don't have to worry about that. Shi Lei jerked Dickens's neck, made him stand up, and said: "You'd better be honest, in two days at most, you will be completely safe." With that, Shi Lei took Dickens and returned to the cave.

When the two divers saw Dickens, they were startled, and their first reaction was to pick up the weapons at hand.

But when they saw Shi Lei, they breathed a sigh of relief, and Shi Lei said: "This person has been handed over to you, tie him up, give him food to eat, and drink to drink." ”

The two divers immediately got up and got busy. 10