I picked up a couple of Pronto filters the other day:
PF 1177 type, PO 4619, $2.69
PF 457 type, PO 5436, $4.12
The PO 4619 says right on it mfg by Hastings. Looks like a good filter except for the button type dome end bypass. Cheaper than a L 10193 and looks like it has more media too. Made in America by an American company.
The PO 5436 actually came in a Dynolube box. No indication who made it, and unfortunately, made in China. It does have GG5436 stamped on the end cap. The O-ring looks suspiciously small like the ST. Other than that, it looks OK.
Both filters were a good price, and the PO 4619 looks better than the $3.50 competition. If I don't find better, I may stick with them.