Canon's budget telephoto with USM motor — faster AF than non-USM versions but still optically poor.
The Canon EF 75-300mm f/4-5.6 USM (1991) is the USM-motor variant of Canon's cheapest telephoto zoom range. The micro-motor USM is faster than the DC motor in non-USM versions but not the ring-type USM found in L-series glass.
Optically poor — soft at most focal lengths, particularly 200-300mm. Low contrast and visible chromatic aberration. Image stabilisation is absent. The USM motor is the only meaningful advantage over the non-USM Mark III version.
Canon EF mount, 58mm filter thread. Full-frame coverage. 150cm minimum focus distance. Micro-motor USM — not ring USM, so still noisy compared to STM or ring USM lenses. 480g weight.
Extremely common and cheap used. Honestly one of Canon's worst telephoto lenses. The 70-300mm IS II USM is vastly superior in every respect. Only worth considering if it comes essentially free with a used body.