Professional ring / aviation spanners for commercial or occasional use 16mm and 17mm long ring spanner aviation Manufactured from C R – v steel for strength and durability 16mm and 17mm double headed spanner One spanner covering 2 different sizes (16mm and 17mm) Total length of the spanner 410mm Extra long design is perfect for when you need extra leverage is needed Suitable for access into restricted awkward areas for example on cambelt etc... Extra long slim shafts Double ended ring spanner so one spanner has 2 rings with different sizes Double-hex / 12 sided ring spanner for maximum grip