Here is an interesting picture from our early testing, showing a collection of different clips that were evaluated during design and development of the MF300 fixture kit.

The clip is an important part of the fixture. It must be flexible enough to close and open easily, and tough enough to withstand normal use.

We evaluated sixteen different designs in two different material thicknesses, along with a couple of different ways to secure the clip to the pressure plate. We bent them and twisted them; we opened and closed a fixture hundreds of times by hand; and we tested their ability to withstand the pressure plate being dropped closed, slamming in to the front panel. As you can see from the broken wreckage some of the designs were not as good as others. In particular we found it important to avoid cutouts and sharp internal corners, which can act as stress concentration points and allow the acrylic material to crack. As you can see, the version we finally settled on is one of the simplest designs.

One of our customers recently sent us some feedback, saying "The fixture door can at times be dropped to a close inadvertently. However, no damage has [ever] been caused by this". It's nice to get positive feedback, and nice to know that the clip can stand up to real-world abuse.