thanks @Jennifer_Ring for confirming the width.
I’m not looking to add new sensors at this time, having recently finished installing a new Ring Alarm system (gen 1). But I was worried the gen 2 contact sensors would be too wide for my old style sash windows (only about 1.5" wide), should I ever need to replace some sensors in the future, or add some extra ones - especially if you stop selling gen 1 sensors. But I see the new ones will fit. thanks.