1 size,,,,same as striker
2 beam,,,as long as possible..
3 beam colour,,more halogen coloured..
4 internal battery,,,to last as long as possible,,built in to handle rather than on top..
5 external material,,rubber if possible,,,but this is not as important as the things above..
6 dimmer ,,and filters,,,,im not bothered about either,,,,but some lads are..
i have the 150 off you dave,,it just needs a few tweeks in my opinion to make it better ,,,the battery on it lasts a good night,,,so thats good,,,if it had a longer beam with a bit more over spill,,,and a mo