It is sterilization (ultraviolet rays have a bacterial effect. turtles are soaked in water for a long time, some parasites & bacteria are prone to grow on their bodies) it promotes the absorption of calcium(promotes the synthesis of vitamin d) it is to provide the uva and uvb ultraviolet light needed for daily use. it improves the appetite of crawling pets and promotes food digestion it is low intensity output, which promotes growth and development .. Color temperature (cct):-2700k(soft warm white) lifespan (hours):-2000 brand name :-aquanature color:-clear lamp base:-E27 POWER-25w,50w,75w voltage-220v-240v. Note- USE THREADING HOLDER FOR THIS BULBS. PLEASE FIND GIVEN LINK BELOW FOR HOLDER- https://www.amazon.in/dp/B07STJGB5H?ref=myi_title_dp note - use threading holder for this bulbbrand name :-aquanature