Appears to be a misidentified Sigma DC DN lens — likely the 16-28mm f/2.8 or similar, not f/1.8.
The Sigma 17-40mm f/1.8 DC DN is listed with an f/1.8 aperture — f/1.8 for a 17-40mm zoom is not achievable with current technology and likely represents a catalog data error. L-Mount.
17-40mm focal length as listed. f/1.8 maximum aperture as listed — likely incorrect. DC DN = APS-C mirrorless. L-Mount.
A zoom lens covering 17-40mm at f/1.8 would be extraordinarily large and has not been produced. The f/1.8 figure in this record is almost certainly a data entry error — compare with id 3471 (Sigma 17-40mm f/1.4, similarly impossible). The actual lens this record refers to may be an entirely different product. Verify from listing and physical inspection.
On the used market verify this record carefully — the f/1.8 aperture spec for a 17-40mm zoom is not achievable. Confirm actual lens identity before purchase. L-Mount as listed.