Let us consider STAP, ISTAR and the 24 hour battlespace. TI is an essential part because neither we, nor the enemy stop when the sun goes down. Let us think about SPYGLASS - which is actually a good bit of kit. Powered by batteries and running on compressed air. Let us think about resupply. To charge the air, the bottles need to go to the rear, to find a CEPA ( Charging Equipment Pure Air, for those that dont know. ) The bottles obvously need to get there, they weigh a couple of kilos each; they need to get back to the OP. Three or four needed per day. Journeys, vehicles, men, time, equipment, possible compromise of position as resupply rocks up. This is because they run on compressed air; batteries are easily portable. The Fire Brigade use TI. Let us consider their resupply requirements: They change batteries. They dont use air. Why is it so easy for them? Why cant we have kit like theirs?