Power Star GB640 battery VRLA AGM 6-volt sealed lead
Replacement Power Star GB640 rechargeable battery pack, valve regulated sealed lead 6-volt 4.5ah batteries with VRLA and AGM technology at low competitive price

If you are using this battery in a portable device that requires manual charging then charge fully when it arrives and first use, charge it as soon as you can after each use, it is when the cells are not fully charged that they slowly start to degrade so keep the energy level up, if they are not being used for long periods then recharge every eight weeks as this will help them overcome the natural self discharge that will occur.
Power Star GB640
Do not leave on a charger for any longer than required to get a full capacity charge, if you leave it on it can start a new charge and over time this will reduce overall lifespan, just charge and remove,

Valve regulated sealed lead or VRLA batteries, they are AGM or absorbed glass mat, the electrolyte is contained within a glass mat between the plates inside the battery so they will not leak, they do not require any maintenance throughout their life, except of course regular charging

The details of this compatible battery pack are offered as a guide, you should check the codes on your old battery before ordering a replacement if your old battery is only 4ah then that not a problem, this one will last longer between charges

Voltage = 6-volts
Capacity = 4.5Ah @ 20Hr
Chemistry = AGM, VRLA

This is a compatible sealed lead battery to replace the Power Star GB640 the overall size is
Length = 70mm or 2.75-inches
Width = 47mm or 2.91-inches
Height = 100mm or 3.93-inches