Tree caps provide a quick access to the tubing bore. Installed on top of AQE Christmas Trees, tree caps allow (bottom hole test adapters BHTA) allow for easy transition from the wellhead and tree to wireline or logging tools. China Tree caps provide a quick access to the tubing bore. Features Available in sizes from 2� 1/16" thru 4 1/16â?? . Working pressures of 5,000, 10,000 and 15,000. Standard in 4130 alloy and some sizes available in 410 stainless steel Learn more information about AQE,you can visit our website.