hello again
it is a 5v 30a relay.
and from what i understand from the datasheet (https://files.seeedstudio.com/wiki/Grove-SPDT_Relay_30A/res/SLA-05VDC-SL-C_Datasheet.pdf), it has a contact voltage of up to 30v meaning it can handle the heater. and it has the option of low or high-level trigger via jumpers
I got it by the way, a 4 channel one since that was the only one available on short notice, and i managed to get the arduino turn the heater on and off.
THANK YOU VERY MUCH 
I will add the transistor the next time I try it.