Instruct: Classify the given Amazon review into positive or negative sentiment.
Query: a waste of money

i originally received the mighty bright adapter and light as a gift. i attached the adapter to the light (no batteries were in the light as directed) and plugged in the adapter, turned on the light; nothing happened - no light. i disconnected the adapter and put in batteries and the light worked great! then i tried the adapter again, w/o batteries, and it still didn't work. so i thought i got a bad adapter and ordered another adapter. i hooked it up and it worked great - for one night. the next night when i turned on the light the light didn't come on; i put in the batteries and the light worked. it's definitely a waste of money to buy this adapter as it's useless.