The REF III Side Handle System Is Primarily Designed As An Attachment For Duty Style Flashlights In Either C-Cell or D-Cell Battery Sizes. For Maximum Defense Effectiveness, We Recommend Either A 5 D-Cell or 6 C-Cell Size Light, Though Others Can Be Used. Propper Training, Such As PR-24 Baton Training, Is Strongly Advised In Order To Fully Realize The Potential Of The REF III. Great For Police, Security and Law Enforcement. Made In USA. Converts And C Or D Cell Maglite Into A Baton.