This disc is amazing! Very true to the numbers. I'd say it has a 5 glide. It's what you want a Trail to be. Thrown flat it turns softly and fades softly. Like a longer rift. Super easy distance. One of DGAs best molds and it is NOT OUT OF PRODUCTION like Infinite says.

This disc flew much better than I expected. I was going through boxes and picked up a SP Undertow that was from a 2019 players pack that hasn't been seen since. I figured I'd test it out against a new Trail that I picked up recently. Honestly, the two fly very similar, and the Undertow had more glide than a expected. Thrown flat, the Undertow had slow turn and finished with a soft fade. It's pretty close to the numbers with a bit more glide, as mentioned earlier. 
 

Verdict: It flies similar to a Trail. The Trail turns a bit later, but both discs are relatively straight flyers with good glide. I'm impressed. 

This is my first DGA brand disc, got it as a mystery disc.  I really like throwing it, it has a very flat top and comfortable rim and flies very true to the -1 / 1 numbers

I have 1 in glow SP and 1 proline undertow. The SP is straight to slightly overstable. It can handle some power and some headwind without turning over. The proline undertow is understable great for hyzerflip with a 75% throw. Throwing it at 90% it turns without coming back.

It's a great control disc for distance, but I can't seem to rip it for a s-line. I either flip it or it fades out to quickly when going for a bomb. But for closer 200 ft drives I can really do some work with the undertow