I am not being paid buy any one and I think the NF coil are the best on the market.
I have used NF Coil Tec and Commander Coils.
I find the NF coils to hold a more even threshold and seem to be stronger at the shaft connector.
I am looking at adding a couple of 16" coils to my collection.
Sense I am guessing you have tried the slandered model and the ultra light.
Which ones would you get for prospecting in uneven ground and rock terrain often found here in Oregon? (I am concerned the ultra light might not be as sturdy as the solid round coils).