RCA Splice

I need to extend my phono cables about .5m as I do not have the funds to re wire the arm I was looking for an RCA splice.
(The arm is a Rega 300)
Is there a prefered brand I should look for.
There are RCA couplers available. I assume you don't really want to cut (splice) the cable.
Radio Shack has a variety of couplers like this

Try Vampire Wire for a coupler. I have no first-hand experience, but I imagine in might be a step-up from Rat Shack.