The dovetail rails on the telescope are customer images, not our own.
We produce dovetail rails in several lengths, you can find theme here:
https://www.baader-planetarium.com/en/accessories/telescope-accessories/dovetail-bars-and-clamps.html?filter_bars_design=254&filter_bars_type=276
There are e.g.
V-120 dovetail, 120mm for Vixen, Celestron and Skywatcher Mounts # 2451650
V-200 dovetail, L= 200mm for Vixen, Celestron and Skywatcher Mounts # 2451661
V-Dove Tail Celestron-orange anodized, 345mm, drilled for Celestron 8“ SC / HD # 2451734
V-Dove Tail orange anodized, 455mm, drilled for Celestron 9.25“ and 11“ SC / HD # 2451745
V rail / dovetail bar 470mm for SC # 2451101
or in custom lengths:
3", V, or Z bars in specified length # 2459800
A similar clamp (but with another knob) is this one:
Baader V-Dove Tail Clamp, Diam. 70mm, with one clamp screw # 2451530