You can pack Endurance Standard recovery boots in your cabin luggage as they weight between 4 and 5 KG. These boots don’t have lithium battery and can thus be packed in any luggage, but you must ensure there’s enough cushion (or soft support) around them to shield them from shocks/damage during bagging handling. Ideally, you can pack the boots in the middle of a clothes bag - the clothes should provide enough shock insulation.
With Endurance Charge system, however, you get a chargeable lithium-ion battery. Most airlines don’t allow lithium-ion batteries in checked-in baggage. For this reason, you can pack the boots in the checked-in baggage but the machine (weighing 1.45 KG, similar to most modern laptops) should go with your cabin baggage.
If your airline does allow carrying devices with lithium-ion batteries in the checked-in baggage, make sure to turn your machine fully off and unplug all wires from it.