We have recently improved the construction of the clip that holds our fixtures closed. This part was originally laser cut from acrylic material and we heard feedback from customers that it could snap if flexed too far. We have changed the material and this part is now machined from Delrin (acetal), a tough, machinable, high-strength thermoplastic. The new part is much stronger than the old. Cosmetically, the only change is that the new part is white (matching the hold-down posts) rather than blue (matching the pressure plate). All fixture kits are shipping with the new clip effective immediately.