Letter opener requires 4 AA batteries (not included). Install the 4 AA batteries in the correct way: 1, Hold the lower cover with your left hand, press the "PUSH" buttons on both sides of the upper cover firmly with your right hand. 2, Take out the internal structure, put 2 AA batteries on the front side of the internal structure (make sure of the +/- direction), and put 2 AA batteries on the reverse side of the internal structure. 3, Put on the upper and lower covers and start working Efficient Electric Letter Opener: Our letter opener envelope slitter can open the envelope in 3 seconds, saving your time. The envelope opener has a cut size of 0.07 inches that won't shred your mail, making it easy for you to better sort your mail. Efficient office supplies can help streamline your daily tasks and improve efficiency Safer to Use: Our mail opener can make your fingers completely free from contacting the blade than traditional letter opener knife, fully protecting your fingers.