For horses and bigger ponys we have a round shape (F for Front) and a longish shape (R for Rear). 
For smaller ponys we have a mixed form of front and rear hoof shape (U for Uni)

F sizes: 290-400 mm in 10 mm steps

R sizes: 285-375 mm in 10 mm steps

U sizes: 225-275 mm in 10 mm steps

Click to enlarge…

Our biggest and smallest front shape F 400 and F 290

Our biggest and smallest rear shape R 375 and R 285

Our biggest and smallest shape for the little ones 275 and 225