The Falcon Eyes Clamps CBH-5 can be screwed onto the SPK-1A background system (with the screws and wing nuts supplied). The clamps allow the standard SPK-1A model to be transformed into a background system suitable for up to 3 rolls instead of just 1. In conjunction with each CBH-5 set used, a B-reel set will need to be purchased, in order for the clamps to be functional.