A clinic stock set of Genia Transcol Elizabethan collars: two each in 7.5cm, 10cm, 12.5cm, 15cm, 20cm, 25cm and 30cm (14 collars). Each has a quick-release fastening. For a single pet, the individual Transcol collar or a collar from the Genia range in the right size is better value.
Sizing
The size is the depth of the cone measured from the neck edge outwards. Measure from the base of your pet's neck to the tip of the nose: the collar should reach just past the nose so the animal cannot get its mouth to the wound. If in doubt between two sizes, go longer for wounds on the legs and flanks and shorter for head and neck wounds, where a very deep cone makes eating difficult. Fit it snug enough that you can slide two fingers under the neck edge.