ITEM NAME:8pcs E-Starter Backplate Back Cover Kit Fit For Vertex 12mm hex one way bearing 8pcs E-Starter Backplate Back Cover Kit Fit For Vertex 16 18 21 SH 18 and 21 CXP 11011 Electric Roto Engines SPECIFICATIONS.8pcs E-Starter Backplate Back Cover Kit Fit For Vertex 16 18 21 SH 18 and 21 CXP 11011 Electric Roto Engines. Item included: 1 x Starter Backplate Kit of 8pcs. Fit for RC 1/10 Vertex 16, 18 and 21 Engines and also SH 18 and 21 CXP Engines.