Penn Plax Super Battery Vac BV-2, Aquarium Vacuum Cleaner. A super-fast, easy and reliable tool for stronger, more powerful cleaning action of aquarium gravel. Features: Telescopic locking extension tube (sufficient for aquariums up to approx 20" (50cm) water depth). Nozzle and Algae Scraper attachments. Can be used as a power siphon for water changes or with the reusable filter bags.- Telescopic locking extension tube (sufficient for aquariums up to approx 20" (50cm) water depth)- Nozzle and Algae Scraper attachment- Can be used as a power siphon for water changes or with the reusable filter bags.