FDM’s all in one kit for Buried Downspouts
How to Select Downspout Adapter
Standard Riser with 90 (not pictured):
Easiest installation for the DIYer. Adapter can be cut with a razor blade knife to your existing downspout as is with no modification.
Upgrade to Vented Wye Cleanout for additional $10 (pictured in photo):
You may have to remove your gutter strap and trim the downspout to make the wye fit. This may require more effort during installation.