Soft neoprene wing covers from Slingshot. Price: 60 € for front wing +  back wing
They are of course perfectly fitted for the Slingshot infinity wings 65, 76 and 84, as well as the 42 and 48 slingshot back wings, but they will fit many other foils on the market. 
 
Here the dimensions of the different covers:
Infinity 65 front: span: 65 cm span, width: 16 cm 
Infinity 76 front: span: 76,5 cm span, width: 26 cm 
Infinity 84 front: span: 84 cm span, width: 30 cm 
Back wing 42: span: 42 cm span, width: 8,5 cm
Back wing 48: span: 48 cm span, width: 11,4 cm