Tenderfoot Heel Incision Device, Preemie for Low Birth Weight, 1000 g - 2500 g; incision (depth/length) 0.85 mm/1.75 mm. Tenderfoot is a safe, gentle and effective heel incision device that is less painful and traumatic to the newborn. Sweeping Arc Technology performs an incision instead of a puncture. Consistent depth and length for a high quality blood sample. Incision depth controlled above the nerve fibers making it less painful. Enhanced user comfort with an ergonomic design for a comfortable grip. Permanently retractable blade for user safety.