Very rare set of 10 different pairs of HL-10 wingtips, with 9 pairs in ceramic and 1 pair in wood, in the original wooden NASA hinged carrying case (23 ¼ x 16 in), with metal NASA tag. 

The HL-10 was one of five heavyweight lifting designs by Northrup, and flown at NASA's Flight Research Center in Edwards, California. With "HL" standing for "Horizontal Landing," the HL-10 was used to study how to safely land a low lift-over-drag vehicle designed for re-entry from space. This set of wing-tips attest to the various stages that the aircraft went through in its development.