I used a 6" Excelerator coil for approx. 1000 hrs. - till it shorted out - what a great coil - made hundreds of great finds with it - ( a lot of 7" to 8" Dimes).
I replaced the 6" coil with a 4.5" x 7" Excelerator coil approx. three months ago - it's fantastic !
I found a 1834 Large Cent at a measured 9" with the 4.5" x 7" this weekend.
This little 'football" coil is the best at getting into tight spots - hits deep - great in heavy iron - pinpoints like a laser and a very important feature - the closed coils like the 5" - 6" and 4.5" x7" 's
don't hang up on brush stubble like the stock coils, 6" x 8" - 10" x 12" 's, etc.
This is very important if you hunt around overgrown houses, in the woods and in brush hogged fields like I do !
Hunting these areas with and open spoked coil will drive you crazy!
I think the reason a lot people have overlooked the 4.5" x 7" is the higher cost - approx. $50.00 more than the 6" x 8" and it's about $80.00 more than the 6".
Anyway you look at it - all three of these coils are great !
Be sure to read Bryce's reviews on these coils - the link is at the top of the Explorer forum page.
Good luck !