WH (Heer) Slip-on for the 'Pionier-Bataillon 220'

Single WH (Heer) Shoulder Strap 'slip-on' ('Überschübe') as intended for a 'Soldat des Pionier-Bataillon 220'. The slip-on is showing the nicely 'chain-stitched' embroidered regimental numbers '220' in black on a fieldgrey woolen background. The black branch-colour is indicating a soldier within an Engineer unit. Hard to find slip-on in very good condition!