This SPLINED privacy twist knob ensures the security of your space, while the brass material provides durability and an antique look. The brass color and unique shape add elegance to any door, whether it's a new addition or a replacement for an existing one. The twist features a  1/4" splined steel shaft. Often referred to as rack bolt - UK For door latch . Also used in the US for auxiliary door locks and other small lock latches used in the early part of the 1900’s especially transom window.