band strut help

Hello, i 'm rebuildin my 904 and i already purchase transgo-3 shift kit with red alto kolene steels, new relined red front band, 4.2 kickdown lever.. etc.etc, but what's the difference between a&a band struts.

There's a heavy duty band strut
http://www.aandatrans.com/Products/904-Heavy-Duty-Front-Band-Strut__12916-2.aspx
and there's a 2nd gear reinforced band strut also
http://www.aandatrans.com/Products/2nd-Gear-Re-Inforced-Band-Strut__32916-2.aspx


I'm confused:-\"