I'll just copy/paste the answer I gave someone the last time we had one of these threads:
They are bayonet drawer slides. The drawers and the inner walls of the box have open square windows punched into the sheet metal. The bayonets "hook" into the windows. When you open the drawer, you'll see 4 bayonets hooked into the drawer; one by each of the 4 corners of the drawer.
The first thing you do is empty the drawer out, then you remove those two small screws on each side of the drawer. After that, extend the drawer all the way out.
Now what you do is hold the left slide with your fingers as you pull up on the front left corner to disengage the front left bayonet.
Now with the left front bayonet still disengaged, support the drawer with your left hand as you disengage the front right bayonet with your right hand.
Now with the left and right front bayonets disengaged, go ahead and disengage the left rear bayonet by pushing the drawer rearward while pulling the left slide toward you with your thumb.
Now with both the left front, right front, and left rear bayonets disengaged; now go and disengage the right rear bayonet. With all 4 bayonets disengaged, pull the drawer away from the slides.
The slides are attached to the inner walls the same way as they are attached to the drawers using their bayonets.
Remember this: Gravity forces the drawer down into the front bayonets -- and the action of pulling the drawer out towards you forces the drawer into the rear bayonets.
But those instructions are for the older boxes that don't have the "claw bayonets" like the KRL Snap-on boxes do. If the new Tech 1000 has claw bayonets in between the regular bayonets, that's going to require the special tool #SPP837 from Snap-on. You can check for claw bayonets by running a credit card along the slides between the slide and the inner box wall that the slide is mounted to. Claw bayonets are not visible from inside the drawer like regular bayonets are.