Danny,
We use these and nothing else in all our machines. The 120A version makes an excellent removable link for a heavy. We use the 75A version for internal conections (Motors, Speed controler, etc) on the heavy and also for the removable link on our feathers. The 30A version is used for battrey and other internal conections on the feathers. As Babeth says, solder, NEVER crimp the contacts. For extra security we always lock each pair with a cable tie as it is not unknown for the 30A versions to unplug under heavy impact.

RS part nos...

120A red... 290-6196
120A Black... 290-6180
120A contacts... 290-6147

75A red... 290-6168
75A black... 290-6152
75A contacts... 290-6118

30A red... 543-985
30A black... 543-979
30A contacts... 543-963

Hope this is of some help

Geoff