STILL-ON Systems is excited to debut all new silicones in 4 sizes!
 
For the correct sizing, gently wrap a tape measure once around the shaft up to 1" behind the head/glans.
That's the number you are looking for. STILL-ON Systems offers a variety of packages for below, average, and above-average girth users. If you are not too sure, we recommend our Universal Fit or Ultimate package, which includes all silicone sizes.
 
Choosing proper silicones in the beginning is a guessing game, because of the external temperatures and blood flow. Here is a rough idea for the silicone sizes below. 
 
Hypoallergenic Below to Above Average Silicones:

Size 1 Soft - Light Yellow - Below 4" flaccid girth
Size 1 Extra Soft - Orange - Below 4" flaccid girth
Size 2 Hard - Sand - Below 4" flaccid girth
Size 2 Extra Soft - Mint -  3.8-4.5" flaccid girth
Size 3 Extra Soft - Blue - Above 4.5" flaccid girth
Size 4 Extra Soft - Red - Above 4.5" flaccid girth
 
Helpful tip - Placing the silicone 1" onto the shaft (behind the head/glans) will allow for more tension.

18 and older to purchase.