Thrust Away With This No-Slip Intimate Grip Masturbator from Sinclair Institute Select. Get a good grip and hang on for thrills when you use this stroker! The Sinclair Institute Select Intimate Grip Masturbator is designed to fit your hand securely as you go for maximum orgasms. The stroker features a no-slip exterior, super-stretchy clear jelly, ribbed tunnel, and open-ended. Dimensions: 6 x 2.5.