Converter Arca Quick Release Plate to Manfrotto RC4 405 Tripod Ball Head Clamp | eBay
Clamp Converter fr 200PL Quick Release Plate to Manfrotto RC4 488RC4 Tripod Head | eBay
Amazon.com : Haoge CP-MAS Quick Release Clamp with RC4 / 400PL Base Adapter Convertor for Manfrotto RC4 System to Arca-Swiss Compatible, Fit 400PL / 405/410 / RC4 : Electronics