DNT Optics IR Delete Cap for TNC335R TNC635R Zulus V2. You remove the IR illuminator and a screw on this waterproof cap in its place to protect the contacts from the elements. The PLUG-M24 is compatible with the ZHD520R-V2 ZHD312R-V2 TNC335R and TNC635R models. Specifications for DNT Optics Plug-M24 IR Delete Cap: Manufacturer: DNT Optics Color: Black Package Contents: DNT Optics Plug-M24 IR Delete Cap DNT Optics Plug-M24: Plug-M24 IR Delete Cap for TNC335R TNC635R Zulus V2