This instrument is a solid-built and very robust bench top product. We tested it, used it, and have been very satisfied for its performance.

Actually the GFF version has similar price but produces better flattened output spectrum. The output power is surprisingly not lower compared to the module without GFF.

It has a key operated output for safety.

The recent modules have buttons, replacing the turning knob at the front panel.

This a good product to buy. Highly recommended.