The Slang have a Drag-flick groove for faster ball acceleration and precision.
Also with the oval endcap of the stick for a more extreme bow shape.
The Lekker Slang have the location of the bow curve at 200 mm and complies with FIH limit with a 24mm bow. 
The handle with an anti-shock foam layer gives an excellent sensation when hitting and stopping.  This option is in 50% carbono / 50% Kevlar and a different design comparing with the other slangs.