Gate Nano SSR and Pico SSR are my favorites. ASG ultimate ones aren't bad too but the Gate ones are far better
possible best 3034 one: http://www.ebay.co.uk/itm/AirFET-NB-non-braked-MOSFET-airsoft-AEG-switch-/191450059625?pt=UK_SportingGoods_Hunting_ShootingSports_ET&hash=item2c93501369
Hmm bit more then I wanted to pay really as I could just get a new trigger block for £25. Any idea if the basic AirFET is ok? Dont want nowt fancy.