Holmarc Opto-Mechatronics Pvt. Ltd. Supplies Swivel Type Post Clamp. Holmarc Opto-Mechatronics Pvt. Ltd. Offers precision manipulators. Swivel Type Post Clamp can be used to achieve three degrees of freedom for post mounted components. Swivel Type Post Clamp is suitable for 12 mm and 16mm diameter standard posts.