ProActive Sports sent me a F4 Turbo Collapsible Resistance Trainer and it is a nicely made product. The F4 Turbo comes out close to the top of the ones I have tried. Very easy to use, it stores nicely in its own sleeve and fits easily into your bag. Sets up quickly and for those that care, it is a good looking product. Weights can also be purchased making and fitted to the end of the shaft. This should make the F4 more effective.

After trying the swing trainer, I found that my lower arms and biceps felt like they had a workout. So if for no other reason, this is a good product to build muscle. What I found interesting that I did not notice with other resistance trainers is that it made me notice my hand rotation, a good thing.

I, as well as other pros Rankmark on the staff, are undecided on all the benefits resistance trainers but we have reviewed a couple and have tried a bunch of them. They will build muscle which will help with swing speed. And the F4 is one of the most convenient of the ones I have tried. As far as creating more lag in your swing, I am still on the fence. Time will tell...

Price: $49.95 - Manufacturer Website