The 30750 Fiber Bundle Sample Compartment has two ports that accept fiber bundles with attached beam probes, and two 1.5 Inch Series flanged ports (one male and one female). A third fiber optic with attached beam probe can be mounted by using the 77803 (male) or 77873 (female) Flange Mounts (sold separately). The fourth port enables detectors to be connected to the Sample Compartment. The 30750 also has a 1/4-20 tapped hole in the bottom, for rod mounting.