Is there a UL listing mark on the Quick Disk? Most of the time, a manufacturer has a UL listing on "the entire system", not just one component. Items identified with a separate UL mark are safe,and suitable for use alone. Hadco's LVC3 was the only pierce point connector that was separately listed and available for our products. They are also made from a glass reinforced Nylon which makes them very durable. On a typical installation for Evening Star, they are placed in the 1" thick sand bed under concrete pavingstones, and must withstand heavy vertical loads without failing.