These are excellent quality mounts produced by Vector Optics in China to extremely precise tollerances. They are fire arms rated and are built for heavy relaible use in the field. Full sizing and specifications are on the spec sheets which can be found in the photos but please do ask if you have any questions. 
On the Vector Optics spec sheets theses Mounts are labelled SCTM-08 = High / SCTM-22 = Medium / SCTM-27 = Low

Product Details:
  • Diameter: 30mm
  • Height - Low, Medium or High (Choose at Checkout)
  • Length: 16mm (0.63 inch)
  • Fits 21mm picatinny and weaver rail
  • High quality rugged aluminum alloy in durable black matte finish
  • Shock proof and heavy duty,Fire Arms Rated and perfect for Premium Air Rifles

Vector Optics are renowned the world over for the rugged robust build quality of their mounts which are produced to extremely precise tollerences using only premium materials. I genuinely believe that there is no better scope mounts availalble in the UK for the same money.

5 Years Warranty:

Your Vector Optics product is warranted free of defects in materials and workmanship for a period of 5 years from time of purchase by the original purchaser. Batteries are not covered under warranty. In the event of a defect under this warranty, we will, at our option, repair or replace the product. This warranty does not cover damages caused by misuse or improper handling. Also, this warranty is null and void if modification or maintenance is provided by someone other than Vector Optics. This warranty is non-transferable.

Delivery:

Free Standard Delivery via Royal Mail included in the price