Unlike most ball transfers, which have metal balls, these have a plastic outer ball that rolls on stainless steel inner balls, so there's no metal-on-metal contact that could create and release particles into your clean room. They've also been ultrasonically cleaned and then individually bagged to prevent dust contamination. These ball transfers were originally developed for the electronics manufacturing industry, where aligning glass layers in monitors and screens must be done without introducing dust. Use them to create conveyors, transfer tables, and material staging areas in your clean room.