This is type B in the description below.
16 spline, 34mm OD. 30mm inner bearing seat. 35mm outer bearing seat. 50mm seal face. 6x161mm wheel bolt PCD (diagonally). Requires pressed in stud M14.
There are possible variants of all parts.
Always compare the dimensions we provide.
FT254.31F.111 (Type A) and FT254.31F.111a (Type B) are not interchangeable. The difference is the location of the snap rings that retain the large gear wheel. Type A snap rings are located on the wheel side of the large gear, Type B snap rings are located on the engine side of the large gear. Bearings to suit this axle are 6206 (inner) and 6307 (outer) with oil seal 50x72x10. 
19 spline. 30mm OD inner bearing seat. 40mm OD outer bearing seat. 50mm OD oil seal.
This is type A in the description below. 16 spline, 34mm OD. 30mm inner bearing seat. 35mm...
This is type B in the description below.
16 spline, 34mm OD. 30mm inner bearing seat. 35mm outer bearing seat. 50mm seal face. 6x161mm wheel bolt PCD (diagonally). Requires pressed in stud M14.