SW-16 - 4-sided for 3.2 mm nipples with 8.5 cm shank
SW-16.3 - hexagon for 3/16" nipple with 8.5 cm shank
SW-17 - hex for 5.0 mm nipple with 8.5 cm shank
SW-18 - hex for 5.5 mm nipple with 8.5 cm shank
SW-19 - hexagon for 6.0 mm nipple with 8.5 cm shaft