BatteryTrader battery compatible with Compaq PRA1400I Computer back up UPS Batteries 12v 18ah There are two 12v 18ah batteries in this set Valve regulated sealed lead acid, AGM Length = 181mm Width = 77mm Height = 167mm More details Our batteries are sealed AGM type which means they are non-spillable, not-hazardous, recyclable, rechargeable and safe for air transport (although always ensure you check with the airline you are taking them on). Valve regulated sealed lead Acid, VRLA, with AGM technology, they will not spill and can be safely mounted on their side. A little help on installation: Once you receive your brand new batteries it is fairly straight forward to swap them with your old ones. Battery Care: Battery care has many myths and different advice round it, here is the tried and tested best ways to look after them. To begin with, fully charge upon delivery and before first use until they are full (should be no more than a few hours), it doesn’t take very long as we ensure our batteries are kept at a high charge. Secondly and most importantly, make sure you charge until full after every use, a fully charged battery will keep that full charge for a good couple of weeks so no need to recharge if it’s not in use for a week. Lastly, if they are not being used for more than 4-weeks then a top up charge will be needed to keep the cells fresh. These batteries are for the standard size 18ah.