S100 model has external battery terminals and is suitable for loads up to 100 W.
S100a model has a built-in internal battery (7.2 Ah capacity) and is suitable for loads up to 100 W.
S100a+ model has both built-in internal battery (7.2 Ah capacity) and external battery terminals and is suitable for loads up to 100 W.
S200 model has external battery terminals and is suitable for loads up to 200 W.
S400 model has external battery terminals and is suitable for loads up to 400 W.
S600 model has external battery terminals and is suitable for loads up to 600 W.
S850 model has external battery terminals and is suitable for loads up to 850 W.
S1200 model has external battery terminals and is suitable for loads up to 1200 W.