VECF (Ventilated, Ejectable Chamber Flag) is an elongated, ventilated dummy round / bolt hold open device / chamber flag that can be ejected like an inert/dummy round.  Machined from solid 360 brass, a detachable and threaded accessory rod is a part of the VECF package, a high vis chamber flag such as CFF (included) can be attached to VECF for increased visibility.

Originally conceived in 2018, the objective was to provide a convenient way for the user to keep the bolt open and allow some air flow inside the bore.  To wit, this can be done by locking the bolt back, it's free and the rifle already has the abillity to do so on its own, though it does open the breach and bore for debris to enter in high wind and dusty environments.  A field expedient way to reduce unwanted objects from entering the breach and bore is to stick a spent casing into the ejection port so the bolt is partially open and out of battery, this is also free

VECF offers a more elegant solution.  When inserted into the chamber, VECF  keeps the bolt open and allows for air flow.  Its body is 2.76: long, the body is hollow, and the rear portion of VECF has a series of perforations, some of which are visible from the ejection port.  As designed in 2018, VECF didn't have the detachable accessory rod, but they reasoned it could be difficult to see from a distance, especially if it was made in brass.  Subsequent design includes a threaded, detchable accessory rod that can be added to VECF to provide more visibility for range use.  VECF doesn't require it to work, they prefer to use it without the rod.

VECF can be removed in 2 ways:

1. If the exgtractor has not engaged the VECF's rim, pull the the charging handle back while using the chamber flag accessory rod as a handle to pulling out of the upper (do not use the chamber flag hamle to cycle the bolt).  If the accessory rod isn't installed, lift the muzzle and VECF will fall out of the chamber.
2. If the extractor has engaged the VECF's rim (it has a rim like a .223 round), pull back on the charging handle and VEC will be ejected like a spent/dummy round.

The choice of material (360 brass) is a compromise between durability and preservation of user's equipment.  They had originally chose 303 stainless steel, it was chosen for durability.  While it's softer than 416R,  they imagine some users might be concerned a stainless steel dummy round could damage their barrels.  Production VECF uses 360 brass instead.  The use of brass does mean the rim of its base won't last forever, VECF therefore should be treated as a consumable.

That said, even if VECF's rim is wholly eroded by the bolt's extractor, it remains usable, with the ejectable feature no longer functional.  One way to preserve VECF's rim is by not letting the extractor fully engage the rim at the base, but this also means VECF is not ejectable.

With VECF in place, the bolt is out of battery, and trigger will not work to drop the hammer.  To remove VECF,  pull the bolt back with the charging handle, and  use the chamber flag handle to pull VECF back and out of the ejection port.  If the bolt's extractor has engaged VECF's rim, pull the charging handle back and VECF will be ejected like a dummy or live round.

They're aware of Hornady's Rapid Rack Empty Chamber Indicator Flag.  VECF was conceived after Hornady's product, though they hadn't seen it till well after VECF was designed.  These products do share a few things in common.  VECF is ventilated and its hi vis accessory rod can't be used to cycle the weapon, the rod itself isn't permanently attached to the body of VECF, but provided as an option, as VECF can be used without it.  Hornady's Rapid Rack is a very good and inexpensive product.

Please NOTE:

• Use the charging handle to cycle the action, do not use the accessory rod, the rod is a high vis chamber flag hanger.
• Do not use the small detachable, threaded chamber flag rod to cycle the action.  If the extractor has engaged the rim of VECF, VECF can be ejected by using the charging handle.  
• VECF is machined from brass. VECF's rim will eventually get worn by the extractor. Like an innert round, VECF is a consumable because it will wear with use.
• VECF is designed to work with 5.56mm AR15/M16 only, do not use it on AK pattern, SIG 551/552/553 and 556, or other 223 auto loading rifles.  It can work on 5.56mm bolt action rifles, but VECF's length isn't compatible with many of them, it'll work as a chamber flag but will not eject correctly.
• Products other than the chamber flag is used for display purposes only.