The main difference between this Telesteps telescopic ladder and the 1600EP model is that the 1600ET is designed more as a tactical collapsible ladder. It has almost the same price, OHSA compliance, and other neat features. What you may notice, however, is that the 1600ET adjustable ladder is that it is marketed as a heavier-duty system being used by the US military.
Despite the fact that it comes with almost identical features and dimensions as the 1600EP, the Telesteps 1600ET is heavier by about 5.5 lbs at 25 lbs compared to the professional-grade Telesteps adjustable ladder. Either of the two should be a good choice for all your climbing chores at home or at the work site; although the 1600ET will come out as heftier for better stability and durability.