Good morning, Karthik;

I agree with BainDarret who suggested that the Sonnheiser "Dryfit" battery is a Lead/Lead-Di-Oxide chemistry battery with a gelled electrolyte. It will not use the same charging algorythm as a liquid electrolyte Pb-PbO2 battery, but it is fairly close to it with the main difference being that the peak charging voltage and the float charging voltage will be a little lower with the "Dryfit." The Nickel-Cadmium charging algorythm is very different from either one of those other two. Please set the selector in the battery compartment to the correct battery chemistry, and use the correct charger intended for your model Metz flash.

Most often, the batteries found with a Metz flash will be the Dryfit. They are a sealed battery.

The optional Nikel-Cadmium battery normally will be clearly marked as being Ni-Cad. There have been some requirements for years in marking Ni-Cad batteries as such.

The liquid electrolyte batteries will have a removable cap or caps for use in replenishing the water (use distilled water, H2O) to bring the electrolyte level back up to the required level AFTER the battery has been recharged. If the electrolyte level is below the top of the plates and grid structure visible inside the battery, add just enough water to bring the electrolyte level up to where it just covers the top of the plates before you recharge it. When fully recharged, then add additional water to bring the electrolyte level up to the top normal level. Normally, it is bad to let the electrolyte level drop to below the top of the plates. Probably you will not be able to fully reclaim or recover the full capacity of the battery if the plates have surface area that has been exposed to the oxygen in the atmosphere. This is one reason why liquid electrolyte batteries do not like to be tilted or laid over on their side.

I have never seen a liquid electrolyte battery in a Metz flash in North America.

I am not really familiar with the Metz 60 CT-4, but I do have and use five (5) Metz 60 CT-1.

If you are in SouthWest British Columbia in Vancouver, there is a very active APUG group there, and over on Vancouver Island also.