CAMERA Support & Rigs Rig Accessories Misc. Rigging Accessories Replacement M4 Thumbscrew (38mm) Watch this product and we will notify you once it is back in stock. The product is now watched We will notify you once the product is back in stock again. E-mail Watch this product Your personal information is processed in accordance with our privacy policy. Replacement M4 Thumbscrew (38mm) Replacement M4 Thumbscrew (38mm)Replacement M4 Thumbscrew (38mm) for the ARCA Swiss clamp portion of the Baseline 15mm LW series.