This Teng Tools 12 piece combination spanner set consists of spanners which have the same dimension at both ends. One end has an open head, and the other has a 12-point ring head, which is set at a 15 degree angle to increase ease of access to the fastening. The spanners are manufactured from chrome vanadium steel for strength and durability and have a satin finish and polished heads. Manufactured to DIN 3113A standards. The TENTT1236 12 piece set contains the following spanner sizes 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, 15mm, 16mm, 17mm, 18mm and 19mm. Supplied in a handy storage tray