Easy to use , but won’t hold a charge [SEP] I love this product it’s a comfortable fit and it heats warms up a bit. I don’t like the whitener I would us this with a different whitener like the Cali smile or glory . I am returning this because it doesn’t hold a charge long enough. Also I don’t like the fact that every four minutes you have to put more whitener on teeth.  I’d rather just put in and wear 16 minutes straight .