Screw locking mounts for each instrument head to allow secure connection to the battery handle "AA" 2 x Cell powered. (Included ) If you're not satisfied with the item while it is in good condition, please return it to us within 30 days. We will either send you a new one or give your money back. If the item doesn't work after 30 days, please take photos or videos and contact us. We will send you a new one as soon as we receive the defective item. Communication is important. Please contact us for any problems and solutions. We promise to reply you within 24 business hours. If you're not satisfied with the item while it is in good condition, please return it to us within 30 days. We will either send you a new one or give your money back. If the item doesn't work after 30 days, please take ph