Jim Howle clown noses are hollow, made of acrylic-coated latex, and come in a variety of shapes and sizes. Jim makes these by hand the old-fashioned way by pouring latex into a mold, layer upon layer until the right thickness is achieved. Each clown nose is then trimmed by hand; expect some minor variations.
SIZING:
To determine proper clown nose size, hold a ruler under your real nose while looking in a mirror.  Measure side-to-side the outside of your nostrils at their widest point.  Match your nostril measurements to the corresponding clown nose size. 
WIDTH: E2 1 1/2", E3 1 1/4"