I mentioned earlier I didnt think the book was too helpful. No size choice available able! To hang a garden sign outside 99. Excellent strain relief here in that critical area causes no problem. So, Ill keep the T90 and the A 20 amp for a very very long time. I was going to try for under water lights but I needed lights for the tractor cab and they are perfect. I do not where it and cross my fingers. So, very happy with the overall battery performance. USB works, Co sensor, not so much.