Specific pannier holder PL ONE-FIT with contoured left side for Trekker Outback MONOKEY® CAM-SIDE configuration 18 mm diameter / The left side case requires an OBKEVS33..R, or a contoured OBKEVS40..R, while the right side accommodates a flat left side case OBKEV37..L or an OBKEV44..L. By mounting the cases upside down, the locking mechanisms are conveniently positioned at the front