This style of desiccator are combined with a single relative humidity indicators which are a visual indication of when the desiccator has fully adsorbed.
All have the same 3/4 x 2OUNS-2A thread but vary in length.
The desiccant cartridge can be unscrewed from the humidity indicator plug went spent and replaced with a fresh unit.
As we are an exclusive distributor of Brownell Limiteds product we can assure that these products comply with their ISO 9001:2015.