smokers Electric Smoker Accessories

For those of you who use electric smokers are there any must have accessories?  I'm looking for a gift idea for a friend who uses a Masterbuilt (not sure of the model #) but I don't have any experience w/ electric smokers.  Are there any tools/accessories that are unique to electric smokers? 
Thanks in advance.  
I can't think of anything. How about a baking steel? He can cook pizza in his oven or on his grill or make fajiatas. It's a good gift imo. The steel is supposed to perform better than the stone. Sorry, no idea on the smoker accessories. Salmon??? ;)
How about a new thermometer?