Don't slay me ! I did a search first !!
I recently stripped down my Lancer 101's and was cleaning the siver bands on the exterior of the 175 drivers. I noticed slight differences in what I thought should have been "Identical" horns. Both say 1217-1290
1. They are different lengths !
2. They mount differently, one has an intregral flange, the other needs a circular clamp like you would use on a 075.
Different production runs ? I can see the benefit of integral mounting flange. But why the difference in horn length.
The HL-87 in the 1976 components catalogue shows the intregral flange.
The 2305 pro from 1974 Pro Catalogue shows the horn needing the external clamp.
Both of my horns show 1217-1290 on them.
Why two different horns that are quite different. THEY WERE PURCHASED BOTH AT THE SAME time on the same day.