Suitable for harsh applications, 300 Series offers torque range of 1,000–1,287,000 Nm and gear ratios from 3.4–5,234. FDK version, with hollow shaft and 2 keys at 120°, uses axial locking ring with threaded holes for reliable shaft mounting. Keyed hollow shaft is available in sizes ranging from 300–310. FZP version, available in sizes from 311–325, features splined hollow shaft which meets DIN 5480 standard, and also includes axial locking key with threaded holes for mounting.