Collet ER, according to standard DIN 6499, form B, type class 2, size ER 50. Brand Gurfer with reference ER50-2.
Also available: set of collets ER, DIN 6499 B CL2, size ER 50, Ø 12,0 - 34,0 mm per 2 mm, 12-piece, in plastic storage case (ref. ER50SET2).
For mounting tools with straight shank.