Schneider 24mm diameter plastic push-on type lens cap.
Beseler #8095 Enlarger Lens Jam Nut (retaining ring) for lenses with 39mm "Leica" mounting thread.
Metal 25mm x .5 pitch lens lock ring (jam nut) to secure lenses with 25mm diameter mounting thread to unthreaded enlarger or camera lensboards.
25mm to 39mm Leica thread adapter for mounting Schneider lenses with 25mm thread on 39mm lensboards.
Omega #421-010 Enlarger Lens Retaining Ring for lenses with 39mm "Leica" mounting thread.
Metal 32.5mm x .5 pitch lens lock ring (jam nut) to secure lenses or #0 shutters with 32.5mm diameter mounting thread to unthreaded enlarger or camera lensboards.
32.5mm to 39mm Leica thread adapter for mounting enlarging lenses with 32.5mm thread on 39mm lensboards.