These Pop-Up Targets by Oncourt Offcourt quickly attach to a tennis net with Velcro� in just seconds. They help focus service practice and improvement of many other strokes, including passing shots, service returns and more. Made of impact resistant nylon with a durable metal frame. The opening of each target measures 19" x 22". Each target folds like a pop-up tent into its own compact 15-inch diameter nylon case for easy space saving storage. Setting up your Pop-Up Targets takes about one minute. NOTE that it should only be set and taken down by an adult since the spring wire that frames each target pops open quickly. It works under the same principle as common pop-up tents and car dashboard protectors. STEP No 1: Pull the Pop-Up Target out of its case and CAREFULLY hold at arm's length. Securely hold the frame and slowly guide the target to its open position. STEP No 2: Hold the target against the net with the open target hole well above the net and the upper Velcro� attachments just below the net band. If playing outdoors on a windy day, place the target on the windward side, so the wind is blowing it into the net. STEP No 3: Pull the Velcro� straps in each of the four positions around the weave of the net to secure each Pop-Up Target in place. If desired you can also trim the longer of the cure it as a target against a chain link fence. STEP No 4: For most, to disassemble and store the Pop-Up Targets is the fun and easy part, but it may take a few minutes of practice on your first attempt. The spring is designed to find its original compact folded position, but you have to firmly guide it into place. Remember that it WILL fit into its original packing position inside the carry case. Be patient and hold the unit firmly as you twist it like a pretzel into position. When properly folded, slide it into its carry case and secure with the Velcro� strip.