Skein Holder (45°/0° instruments only)
This is a device for measuring yarn skeins. Wind the yarn around the skein holder in multiple taut layers until it is effectively opaque and is as flat as possible. Secure it in place with the detachable arms on the sides of the skein holder. Place the skein holder at the sample port and back it with the sample clamp or a white backing tile to provide a consistent background and pressure. Make several measurements of the skein, rotating the holder 90° between measurements and averaging the readings for the final result.
1.25-inch Glass Port Insert (45°/0° instruments only)
This option provides a snap-in port plate with an opening one inch in diameter that is covered with glass. The glass insert protects the inside of the instrument from sample and airborne particles. Remove the standard port insert by pulling it out of the port insert retainer. Replace it with the glass port insert. Make sure that the flat portion of the insert is facing outward with the beveled portion toward the interior of the sensor. Then standardize the instrument with the glass in place. However, you should check measurements of the green and white tiles and perform any other diagnostics without the glass cover. Difference measurements using a glass cover will be more accurate than absolute measurements.
1.25-inch UV Port Insert (45°/0° instruments only)
This port insert contains a 420-nm filter to prevent light below 420 nm from hitting the sample. Remove the standard port insert by pulling it out of the port insert retainer. Replace it with the UV port insert. Make sure that the flat portion of the insert is facing outward with the beveled portion toward the interior of the sensor. Then standardize the instrument with the UV filter in place. However, you should check measurements of the green and white tiles and perform any other diagnostics without the UV filter.