DT Swiss ProLock spoke nipple

uses black Park Tool spoke wrench

Pro Lock® is a process where a patented, dual compound, adhesive liquid is injected into the nipple thread, allowing for extremely durable wheel builds. By threading the nipple onto the spoke the adhesive is activated and starts to harden. Re-truing the wheel is still possible after the adhesive has hardened completely, with only a minimal decrease of its thread-lock function