These ones from Maplin are fantastic. V bright, small, light and cheap.You can clip them on your front when working with both hands. Can spot blood well. I have a couple of them. 8 LED Pocket Light | Maplin
The new one from LED lender is fab, p7qc... White, green, red and blue. The blue is close to UV so really shows up organic matter all colours also run at 220 lumens on full power... Really impressed with mine
I have found that the brightness of the LED is actually unhelpful to me. I can see blood spots best with my old 3 cell Maglight torch, that throws a more yellow(ish) light.
However since my Labrador bitch has been trained, I locate the spot, mark it and then fetch her. If I thought it was a proper runner, then I would leave it until the morning before following up.