HANS IV - Medium - SFIHANS IV Sliding w Post Anchor size Medium The new HANS Device IV, now offered in 3 different size and at a lower price. The Hans IV is an improved FHR (Frontal Head Restraint) that is 10% lighter than the previous Hans III. Custom molded pads which nest into the device, preventing slippage, were designed with an upgraded foam for improved comfort and support. Offered in a 20 degree option suitable for most sedan type cars with a more upright seating