The spring loaded brass window center punch by LINE2design is made with a knurled brass body for a secure grip and durability, and a stainless steel point for quick, sharp, and accurate piercing of window glass for all types of emergency entries. Great for Firefighters, EMS, Police and anyone who wants peace of mind. Use the heavy head to align with the positioning point. Firmly press the handle and press it in the direction of the punch. After the punch is pressed back into the rod for a short period, the strong spring will vigorously eject the punch.