Just bought the gun and a new A/C bottle from Halfords and recharged my Vee. After the engine came out I never had a chance to recharge the system again so bought the kit from Halfords. You connect the trigger hose to the low port and then fill the system until it falls between 25 and 30psi. Took me 2 mins and afterwards had icy cold A/C again in the vee. I paid £50 for the whole kit and got £10 back for returning the bottle. Now, in future all I have to do is purchase another bottle and top up once a year if it ever gets low. Easy.