Canon Macro Twin Lite MT-24EX m42 adapter as you might have guessed

as you might have guessed

The top thread is reversible to accommodate either a camera (with a 1/4" thread) or a head (with a 3/8")

Toyos are well made

unfortunately missing nameplate

Canon Macro Twin Lite MT-24EX m42 adapter as you might have guessedThe Canon Macro Twin Lite MT 24EX is a versatile macro lighting system with a lens mounted ring and a pair of compact flash units that can be placed freely along their ring segment and tilted independently. The lens ring clips on to the EF 50mm f2. 5, EF 100mm f2. 8 (non IS), and MP E 65mm f2. 8 macro lenses; it can be attached to others with the use of suitable Canon Macrolite adapters (a 52mm ring is included). The MT 24EX has full manual or E TTL