This 2" to 1.25" adapter makes 17.3mm and 14mm Delos models parfocal with most Tele Vue 1.25" eyepieces (including other Delos focal lengths) that use the Paracorr Type-2 reducing adapter.
Comparison of Delos eyepieces in Paracorr Type-2 using In-Travel adapter and Paracorr's reducing adapter. Both eyepieces can be set at Paracorr's Tunable Top position "D":
Comparison of In-Travel adapter to Paracorr T-2 and High Hat adapters. Note how the interior eyepiece holder is counterbored on the In-Travel adapter. Unlike the other adapters shown, this allows the In-Travel adapter to seat the eyepiece below its top surface.