Having tested the ST400, I didn’t want to give it back. Great for post fencing and I look forward to it working on insulators. Very fast: I did a fence that would have taken me 5 hours in only 1 1/2 hours and the worker I assigned the job was back at 9am. I asked him "why he was back", he said "it was because he had finished the job". What a labour saver, I can charge the same but get the job finished quickly and onto the next job.