Used by SOE these could well have been home made and used by Auxiliers. They were made in a few different designs.
Images show;
Caltrops 4-point - used as an anti personnel weapon most effective when used against wheels with pneumatic tyres. This solid metal, four point caltrop has sharp points arranged in such a manner that one of them always points upward from a stable base.
SOE-type 2-point caltrop used as an anti personnel weapon most effective when used against wheels with pneumatic tyres. This metal, two pointed caltrop has sharp points and designed in such a manner that one of them always points upward from a stable base.
Star type caltrop used as an anti personnel weapon most effective when used against wheels with pneumatic tyres. This solid metal, star shaped caltrop has sharp spines arranged in such a manner that one of them always points upward from a stable base.
Tyre slasher rings of various designs were issued to SOE.