1. Dip Bar Station - Attachment for 2"x3" Rigs and Squat Racks with 5/8" Hardware / Angular Bar Layout (Click Link to Check Price on Amazon)
Editor's Rating : 9.7 out of 10
Fits all racks with a 2" x 3" 11-gauge steel and 5/8" holes.This dip bar has rubber handles to prevent slipping and provide better grip.

2. Dip Station - Attachment for 3"x3" Rigs and Squat Racks with 5/8" Hardware / Angular Bar Layout … (Click Link to Check Price on Amazon)
Editor's Rating : 9 out of 10
Fits most rigs or squat racks with 3"x3" uprights with 5/8" holes.Tapered handles so you can work different muscle groups: narrow or wider grip.

3. BodyCraft Versatile and Heavy Duty F430 Squat Rack With Extra Bar Hooks And Dip Attachment (Click Link to Check Price on Amazon)
Editor's Rating : 9.9 out of 10
Built for people who know how to push their bodies to the limit, the BodyCraft F430 power rack delivers a powerful workout performance. By itself, the F430 is ideal for squats, lunges, and other leg exercises, with a pair of adjustable spotter arms and bar catches making solo workouts safe and efficient.However, you can also combine the power rack with a host of other BodyCraft strength-training attachments, including a lat/low row station, a cable crossover attachment, dip handles, and a flat/incline/decline bench.

4. Titan T-2 Series Dip Bar Attachment for Power Rack Strength Training Workout (Click Link to Check Price on Amazon)
Editor's Rating : 9.3 out of 10
- Fits any T-2 Series Power Rack (with 2"x2" tubes) - 1" steel hooks for maximum durability- Installs in seconds - Durable finish

5. Body-Solid DR378 Dip Attachment for GPR378 Power Rack (Click Link to Check Price on Amazon)
Editor's Rating : 9.8 out of 10
For use with Body-Solid GPR378 Pro Power Rack ONLY (sold separately)Heavy Gauge steel for extreme workouts. Large 1.5" diameter grips for extra comfort