ER spanner wrenches are manufactured to factory specification and dimensions to achieve optimal clamping force use of ER spanner wrenches on ER NUT prevents over-tightening and breakage. ER spanner wrench flats are made to ER NUT specifications, conventional spanner wrenches may not work on ER NUT.

Model	I (ringent size）	L(length)	B(head size)	Collet type
ER11A	17	117	35.7	ER11-A
ER16A	25	146.5	53.5	ER16-A
ER20A	30	166	62	ER20-A
ER25-UM	37	210	62.5	ER25-UM
ER32-UM	46.5	249	74	ER32-UM
ER40-UM	58	292	86	ER40-UM
ER50-UM	74	351	110	ER50-UM
S/ER25	38-42	167		ER25-UM
S/ER32	45-52	190		ER32-UM
S/ER40	55-62	215		ER40-UM
S/ER50	78-85	262		ER50-UM
ER8M	8	75	13	ER8-M
ER11M	11.5	95	17	ER11-M
ER16M	15	117	22.5	ER16-M
ER20M	19.5	129	28.5	ER20-M
ER25M	25	142.5	35.5	ER25-M