Rossiter Fittings produces two models of pipe fittings for underwater lines. The two models $($RF$-12$ and RF$-25)$ have the following characteristics, as developed by a product cost analyst:

RF$-12$ RF$-25$

Selling price per unit $ $372$ $ $512$

Variable cost per unit $ $292$ $ $352$

Expected units sold per year $3,42911,811$