The Bellows Set for UMB-1 Universal Matte Box replaces or restocks the bellows assembly fitted to the UMB-1. It centres on a 143mm diameter bellows ring with a 138mm round polariser slot, carrying a rubber bellows with a 114mm standard opening at the lens end. A complete set of reduction rings is included, snapping into the bellows quickly for fast lens transitions between setups. The reduction rings use specially designed tabs that also fit third-party 114mm threaded bellows, so the set can serve outside Wooden Camera's own accessory range as well as within it. It is a standalone bellows assembly rather than a variant of the matte box body itself, supplying the light-sealing, lens-clearance component that the UMB-1 configurations otherwise ship with as standard.