Blue Fireball Empty 2" Filter Cell with Retaining Ring

Stock count is accurate & shown in real time.
- This item is out of stock.
- Sign up for back-in-stock alerts to be notified when this item becomes available (account login required).
- This item is out of stock.
- Sign up for back-in-stock alerts to be notified when this item becomes available (account login required).
Contiguous US / Lower 48:
Free shipping applies to orders over $50 using our chosen carrier/method. Faster paid options are available at checkout.
Alaska, Hawaii & US Territories:
Free shipping applies to many—but not all—products. Enter your ZIP code in cart or upon checkout to confirm options and costs.
International:
International orders do not qualify for free shipping. Shipping, duties, brokerage, tariffs, and taxes are the customer’s responsibility. Some items may be restricted due to export, size, or manufacturer limitations.
- Buy 3 for $12.00 each and save 14%
Description/Uses:
- 2" empty filter cell for astronomy filters
- Great replacement for old, worn filter cells or those with threading issues
- Will accept filter substrates between 45mm and 47.2mm in diameter. Please measure your glass filter before purchasing this item to ensure fit.
- Can also be used as a 2" 7.7mm long spacer ring
Features:
- Precision machined from aluminum and black anodized
- Has standard 2" filter threads (male on one side and female on the other)
- Threads into any standard 2" eyepiece, barlow, diagonal, camera nosepiece, and accessories with compatible female thread
- Includes retaining ring with two notches 180-degrees apart to hold glass filter substrate within filter cell
- Made in Taiwan
Specifications:
- Total length of filter cell = 0.42" (10.7mm)
- Extension provided = 0.30" (7.7mm)
- Length of external male thread = 0.12" (3.0mm) including unthreaded undercut; 0.06" (1.5mm) excluding undercut
- Thread specification (external thread) = M48x0.75 male
- Length of internal female thread = 0.24" (6.1mm)
- Thread specification (internal thread) = M48x0.75 female
- Maximum outside diameter = 1.99" (50.7mm)
- Retaining ring length = 0.12" (3.0mm)
- Will accept unmounted filters between 45mm and 47.2mm in diameter and up to 3.1mm thick
Other Information
- Country of Manufacture: Taiwan
Description/Uses:
- 2" empty filter cell for astronomy filters
- Great replacement for old, worn filter cells or those with threading issues
- Will accept filter substrates between 45mm and 47.2mm in diameter. Please measure your glass filter before purchasing this item to ensure fit.
- Can also be used as a 2" 7.7mm long spacer ring
Features:
- Precision machined from aluminum and black anodized
- Has standard 2" filter threads (male on one side and female on the other)
- Threads into any standard 2" eyepiece, barlow, diagonal, camera nosepiece, and accessories with compatible female thread
- Includes retaining ring with two notches 180-degrees apart to hold glass filter substrate within filter cell
- Made in Taiwan
Specifications:
- Total length of filter cell = 0.42" (10.7mm)
- Extension provided = 0.30" (7.7mm)
- Length of external male thread = 0.12" (3.0mm) including unthreaded undercut; 0.06" (1.5mm) excluding undercut
- Thread specification (external thread) = M48x0.75 male
- Length of internal female thread = 0.24" (6.1mm)
- Thread specification (internal thread) = M48x0.75 female
- Maximum outside diameter = 1.99" (50.7mm)
- Retaining ring length = 0.12" (3.0mm)
- Will accept unmounted filters between 45mm and 47.2mm in diameter and up to 3.1mm thick
Description/Uses:
- 2" empty filter cell for astronomy filters
- Great replacement for old, worn filter cells or those with threading issues
- Will accept filter substrates between 45mm and 47.2mm in diameter. Please measure your glass filter before purchasing this item to ensure fit.
- Can also be used as a 2" 7.7mm long spacer ring
Features:
- Precision machined from aluminum and black anodized
- Has standard 2" filter threads (male on one side and female on the other)
- Threads into any standard 2" eyepiece, barlow, diagonal, camera nosepiece, and accessories with compatible female thread
- Includes retaining ring with two notches 180-degrees apart to hold glass filter substrate within filter cell
- Made in Taiwan
Specifications:
- Total length of filter cell = 0.42" (10.7mm)
- Extension provided = 0.30" (7.7mm)
- Length of external male thread = 0.12" (3.0mm) including unthreaded undercut; 0.06" (1.5mm) excluding undercut
- Thread specification (external thread) = M48x0.75 male
- Length of internal female thread = 0.24" (6.1mm)
- Thread specification (internal thread) = M48x0.75 female
- Maximum outside diameter = 1.99" (50.7mm)
- Retaining ring length = 0.12" (3.0mm)
- Will accept unmounted filters between 45mm and 47.2mm in diameter and up to 3.1mm thick
Other Information
- Country of Manufacture: Taiwan

Blue Fireball Empty 2" Filter Cell with Retaining Ring
