Well ... is not really much to say,
it's just a big flat cold pack with a class "cooling capacity".
Dimensions: (32.0 x 24.5 x 1.4) cm
But note this battery is available from Amazon several times.
1x as "Gelert cold packs Freezerboard Cooler 800" for 9.99
and ...
1x as "Thermos cold pack Frezze Board 800g" for current 7.64.
Keep your eyes peeled when buying battery: -D