The Bridge Drop-in/Lift-out Clamp uses a ball plunger to hold the rail in place. If needed , adjustments to the ball plunger can be made using a small screwdriver. The clamps work well with all Code 332 rail with a flange width of 7.0mm to 7.5mm. (Micro-Engineering, Llagas Creek Railways, etc.) The clamps are built with Stainless Steel 6-32NC Socket Head Cap Screws (SHCS) requiring 7/64 tool.