6MIK have introduced a new Optima black shiny fuel line for nitro engine. This 2x6mm premium fuel line is made from high-quality and durable silicone and won’t harden or crack and remains flexible. 
The Optima black shiny fuel line is super durable and doesn’t kink when coiled and grips really well on to your engine and pipe fittings

Optima Black fuel tube (1m) super high quality