Both Striker HT and ULT trousers are aimed at warm conditions, but the decision still comes down to work rate, durability requirements and the equipment you carry.
The Striker HT in Multicam is a proven hot-weather option with the pocketing and protection expected from a combat trouser. The Striker ULT in Brown-Grey and Multicam Black should be compared where minimum weight and ventilation are high priorities.
Do not choose solely from a studio photograph. Look at the fabric zones, pocket access under a belt or harness, knee-pad compatibility and how the waistband works with the load you use. A feature is useful only if it remains accessible.
Hot-weather clothing cannot remove the need for pacing, hydration and sun management. Lighter fabric may improve comfort but can involve a trade-off in abrasion resistance. If most of your use is through scrub, around sharp equipment or on rough surfaces, factor that into the choice.
Measure carefully and use the current size chart. Try the trousers with the belt, footwear and knee protection you intend to use, then check movement through a squat, climb and kneel before committing them to a long day.