There are many different types of ski rails and boxes, I will show a few
This is the common flat box. The length and width vary
This is an A-box. Once again the lengeth and width vary.
This as a Raimbow Box. The length and Width vary.
This a bannana Box. The length and Width vary.
This is a Drop Box.The length and Width vary.
This is a C box. The length and Width vary.
This is a flat down box or a down flat box. The length and Width vary.
My Fourth Website Snowparksolutions Which has more rails and more info