Monica Garcia : r CurvyNewsWomen Purple Triangles. The Hidez Compression Hood works on the facial pressure points to help promote calmness and focus in nervous, unsettled, or anxious horses. It can also help increase poll flexion and provide relief for chronic Temporomandibular Joint Disease (TMJ) soreness. Miniature : Small 6 7HH, Medium 7 8HH, Large 8 9HH Small Horse: Small 8 9HH, Medium 9 10HH Shetland: Small 10 11HH, Medium 11 12HH Pony: Small 11 12HH, Medium 12 13HH, Large 13 14HH Horse: Small 14 15HH, Medium 15 16HH, Large 16 17HH, XL 17 18HH XXL 18 19HH XXXL 19 20HH