The Canon EF 300mm f4 Features

Focal length and maximum aperture: 300 mm 1:4
Lens construction: 15 elements in 11 groups
Diagonal angle of view: 8°15'
Focus adjustment: Rear focusing system with USM
Closest focusing distance: 1.5m / 4.9ft
Filter size: 77mm

The Canon 300mm f4 includes:
77mm Snap-On Lens Cap, Lens Dust Cap E (Rear), Tripod Mount Ring A (W) for 70-200/300/400, LZ1128 Lens Case and User Manual