Made of high-quality silicone material, durable and corrosion-resistant. Simple and convenient to use with high performance. Engineered design improves tightness and helps prevent internal slippage. Features a wear-resistant silicone rubber head for a secure grip on helicopter start levers or fixed-wing prler shields. Compatible with Mayatech TOC80 electric RC models. Size Chart: L: Outer Diameter Approx. 52mm / 2.05 inches; Inner Diameter Approx. 45mm / 1.77 inches; Height Approx. 30mm / 1.18 inches S: Outer Diameter Approx. 36mm / 1.42 inches; Inner Diameter Approx. 24mm / 0.94 inches; Height Approx. 30mm / 1.18 inches Package Includes: 1 x Engine Starter Silicone Head Note: 1. Please allow slight measurement deviation due to manual measurement. 2. Due to differences in monitor displays, the actual color may vary slightly from the image.