It's a KR808D-1
And it's a slim ecig so it should only be using single coil standard resistance (2.5 to 3 ohm) cartos or attys
In general, 100mah of charge is 1 hour of moderate vaping w/ standard resistance attachments. I consider moderate to be less than 1/2 the time.
If your battery alone is about 65mm then you have 180mah batteries
If your battery alone is about 78mm then you have 280mah batteries
and this is typical for some other slim models too.
KR808D-1 also has an XL battery that is (I think) almost an inch longer than the 78mm one and those add another 100mah
When people move to fat battery models (Ego, Kgo, Riva, etc) and mods 450mah+ then they can also use hotter low resistance (lower ohms) cartos and attys, or dual coil ones (more vapor instead of hotter) and then 100mah does not last an hour - it lasts less. The lower the ohms the faster the battery charge is used.