You need 4.5 mm, Duotone sells it at an incredible mark up. I think I payed around 18 euros for 2 meters of it. The first line probably lasted me 20 sessions. If it happens again I am selling it....

Boil your formuline in hot water to get all the soap out of it or old formuline works fine.

You need the Fomula X rope

It's a variant of the formuline also made my Marlow.
Same as formuline but less rigid so it can cleat more easily.

You can see both Formuline and Formula X picture on their webpage:

shop.marlowropes.com/en-gb/formuline-efl

Or unless you adjust on water all the time, buy a normal extension and save time, $$, heartache about special rope when u need it. Fan of simple .....

jusavina said..
You need the Fomula X rope

Incorrect.

What are you talking about?

The correct rope is LIROS rope not Marlow (who manufacture formula X).

I think you might find it is 4.5mm not 3.8mm.

www.duotonesports.com/en/products/power-xt-2-0-sls-14220-7303

onshoreroy said..
Sorry if this is he wrong section , does anyone know the correct rope for an uni xt extension? I changed to forum line and it slips when rigging all the time, I thought the extension had worn out, but it is 2 years old and guys at the beach have 10 year extensions that are still going strong.

The rope that comes with the duotone ratchet extension (not sure about their regular extensions) is slightly thicker than the formuline you can wet at a windsurf store. The original rope is expensive/marked up but unless you are ratcheting the sail to rig fast like a madman it should last you a long time (years). Yes, I would ratchet big cammed sails crazy fast so some parts of the rope didn't grab. I flipped the rope and started ratcheting at a normal pace and the problem was gone.