- Adjustable & Stable Alligator Clamp- Kemimoto boat cup holder with a 360°adjustable high-quality aluminum mounting clamps, clamp firmly on the rails of your boats and side tables, have an impressive grip that won't slip, securely hold your drinks and cups. Easy to install and use. With a skid-proof pad, it will be more stable and protect the rails. Stable without sliding for 0.6-1.75" rails and vertical bar.