Here are a few quick measurements of the Peerless BC25TG15-04 1" Silk Dome tweeter. 

These were taken for some preliminary testing of a custom IEC style baffle attachment I built for my turntable in order to take clean & presentable half space measurements of drivers.

This was an excellent tweeter that was also priced really reasonably.  A low distortion tweeter with very shallow waveguide profile on the face plate that helps gives it a smooth response both on and off axis.  It's too bad Peerless / Tymphany decided to shift away from the DIY market.

The On/Off axis measurements were taken at 2v / 50cm and scaled -3dB (equivalent 2.83v/1m level).  Distortion measurement taken at 2v / 10cm (1W nominal). 

Measurements gated at 7ms, Smoothing applied is 1/48th octave.