Thanks for watching this tutorial by Safe Jack! If you're having any trouble getting the measurements in the video, please call (509) 735-2106 Monday-Friday 8am-5pm Pacific and a representative will be happy to help you! Alternatively, you can email us: info@safejacks.com with your questions. If you have the measurements and are ready to order your Custom Extension Screw Collar, please follow this link: safejacks.com/products/custom-extension-screw-collar