Rex Specs come in two sizes. The Large (Original) fits most dogs between 30-100+ lbs with some success on either side of this range. The Small Goggle fits dogs between 10-30 lbs. However, the fits depends a lot on the shape of the dogs head and facial structure.

REXSPECS SMALLGOGGLE

JJ / Shih Tzu /12lb

Lloyd / Boston Terrier / 16lb

Robin / Basenji mix /19lb

REXSPECS ORIGINALGOGGLE

Kona / Blue Heeler / 30lb and Cali / Red Heeler /27lb

Macintosh / Standard Poodle / 60lb

Oliver / Vizsla / 65 lb

Piper / Border Collie / 57lb

Remington and August / Blue Great Danes / 160lb

Ricky / Belgian Malinois / 75lb

Rio / Black Lab / 90lb

Tuckerman / German Shepherd mix /90lb

Yaz / Alaskan Husky / 55 lb

Zyker / German Shepherd / 80lb