As hermit crabs grow, they need larger shells to change into. Always keep extra shells in their enclosure. These extra growth shells should be larger than the shell your crab currently resides in. It is also recommended to keep different sizes of shells in your enclosure for your crab.
I purchased 2 of these lights to go on a 40 long tank and I like the look of the lights sitting above overhead the tank.
Of course they have 2 settings one which is a soft blue for evening.
The quality and price have pleased me too.