This is a Tokina-made lens that comes with a Canon EF mount. The lens has a maximum ƒ/2.8 aperture and a minimum ƒ/32.
From Amazon
TOKINA atx-i 100mm Macro F2.8 Canon EF
HDEW Cameras
Tokina ATX-i 100mm F2.8 FF Macro (Canon EF)
OnBuy
Tokina ATX-I 100mm f2.8 FF Marco Lens (Canon EF)