Hot Spring Spas and Caldera Spas have a special cover lifter that screws directly to the spa cover. This option adds the special metal mounting brackets into the spa cover. The models of spa cover lifters this accommodates are;

Hot Spring Spas - CoverCradle® RCS
Hot Spring Spas - CoverCradle® II RCS
Hot Spring Spas - UPRITE® RCS
Hot Spring Spas - LIFT 'N GLIDE
Hot Spring Spas - GLIDERITE® RCS
Caldera Spas- ProLift Cover Lifter
Caldera Spas- PivotPro® Cover Lifter