The 021-0127 Battery Tender Junior's lightweight, compact size makes it ideal for those hard-to-fit spots. The trickled charger with a brain will assure batteries are maintained after charging and allows ready to go! - Fully automatic two-stage lead-acid battery charger. Perfect for all lead-acid, sealed maintenance free and gel cell batteries. - After reaching peak 7.2 VDC, charger automatically switches to 6.6 VDC float voltage. - When voltage drops below 6.3 VDC, charger resumes charging back to 7.2 VDC. - Solid state two color LED indicates stage of charger. - Spark proof. - Reverse polarity protected. - 12' output cord. - 5 year warranty!