A system including apparatus and methods for compressively retaining cargo to a vehicular surface may, upon adjustment, frictionally engage the underside of the upper lip of a truck bed sidewall and transmit a compressive force to a cargo retention element positioned substantially above vehicular cargo. A vertical compression force enhancement element, which may be the same as an adjustable vertical compression force transfer element, may be a threaded rod and threadably mated nut system. The invention also discloses an extendable vertical compression force base element to fit differently sized truck beds, for example.