Kupo 40" Extension Grip Arm: Offset Lighting Without a Boom

Why the Kupo 40" Grip Arm Replaces a Boom for Off-Axis Light

A boom is the usual answer when you need a light or modifier off to the side, but it is not the only one. The Kupo Black 40" Extension Grip Arm with hex baby pin gives you a 40" (108.58 cm) steel arm that mounts into a 2-1/2" grip head, so you can position a flag, scrim, silk, or small fixture away from the stand's center column without a full boom assembly.

The arm is 5/8" (16 mm) in diameter with a machined rough texture for a non-slip surface. The hex pin end is designed to prevent heavy light fixtures from twisting under their own weight, which matters when you are reaching out rather than shooting straight down. This is offset lighting without a boom in the practical sense: the arm extends your reach, but it still depends on the stand and grip head for support.

Kupo Extension Grip Arm Setup: Mount, Extend, Lock

Work from the stand outward. The grip head is the anchor, and the arm is only as stable as the clamp that holds it.

1. Mount the grip head to your stand: The 2-1/2" grip head consists of a pair of rotating aluminium discs attached to a 5/8" (16 mm) receiver. Fit the receiver onto your stand's baby pin or stud, then tighten the oversized ergonomic T-handle. The head uses a non-slip aluminium friction disc and a solid steel central bolt with a fixed solid pin to secure it to the aluminium casting.
2. Insert the 40" arm into the grip head jaws: The discs have four different sized V-shaped jaws to accept accessories with a 5/8", 1/2", 3/8", or 1/4" mounting stud or tubing. The V-shaped jaws have teeth that grab whatever is mounted between the plates securely. The arm's 5/8" (16 mm) tubing fits the largest jaw.
3. Set the arm angle before adding weight: Loosen the T-handle just enough to rotate the discs to your intended angle, then tighten. The roller bearings are designed for maximum torque, so you can apply firm pressure without fighting the handle.
4. Attach your accessory at the hex pin end: The hex pin end prevents heavy light fixtures from twisting under their own weight. Mount your fixture or grip accessory there, then recheck the grip head tension.
5. Add counterweight at the short end: The arm is 40" long, so any load at the far end creates leverage. Use a sandbag or counterweight on the short end of the arm or on the stand's base before you let go. The catalog does not specify a maximum load or a required counterweight, so start light and test stability before adding more.

What the Kupo Grip Arm Actually Gives You

• Kupo Black 40" Extension Grip Arm with hex baby pin: The KUPO Black 40" Extension Grip Arm with hex baby pin handle is a 2 1/2" grip head mounted on the end of a 40" piece of steel tubing 5/8" (16mm) in diameter. The 40" length is what lets you offset a light or modifier from the stand, and the 5/8" tubing is the standard size that fits the grip head's largest jaw.

  

• Kupo Black 40" Extension Grip Arm with hex baby pin: The Hex pin end prevents heavy light fixtures from twisting under their own weight. When you extend a fixture sideways, gravity tries to rotate it. The hex pin is the feature that resists that twist, which is central to safe offset lighting.
• Kupo Black 40" Extension Grip Arm with hex baby pin: The discs have four different sized "V"-shaped jaws to accept any accessory with a 5/8", 1/2", 3/8" or 1/4" mounting stud or tubing. This is the compatibility range for the grip head, so you can mount the arm itself or other grip accessories without a separate clamp.

Grip Arm Counterweight Tips for Offset Loads

The Kupo arm weighs 1.42 kg and is made of aluminium with a steel bar, so it is manageable to handle, but a light fixture at the end of a 40" lever still changes the balance of the stand. The catalog does not supply a maximum load rating or a counterweight formula, so treat counterweighting as a stability check rather than a fixed recipe.

Place counterweight on the short end of the arm or on the stand's base, and keep the arm's long end over a clear area so it cannot swing into people or equipment. If the stand feels top-heavy when you loosen the grip head, add weight before you continue. The non-slip aluminium friction disc and the T-handle are designed for positive locking strength, but they cannot compensate for an unstable stand.

Studio Grip Arm Safety Checks Before You Walk Away

These checks use only the features and dimensions supplied for the Kupo arm. They are not a substitute for your own risk assessment.

• Check the grip head jaw size: The minimum jaw diameter is 6.35 mm and the maximum is 16 mm. Confirm your accessory stud or tubing falls within that range before mounting.
• Confirm the hex pin is seated: The hex pin end is the anti-twist feature. Make sure the fixture is fully engaged on the pin before you tighten anything else.
• Re-tighten the T-handle after loading: The grip head uses a solid steel central bolt and a fixed solid pin. After you hang a fixture, check the T-handle again; leverage can reveal a loose clamp.
• Keep the arm's swing path clear: A 40" arm can sweep a wide arc when you rotate the grip head. Clear the area below and around the arm before you loosen the head.
• Do not exceed what the stand can support: The supplied information does not include a load rating for the arm or a stand compatibility list. If your stand feels unstable with the arm extended, reduce the load or use a different support.

When the Kupo Grip Arm Is the Wrong Tool

The Kupo arm is a grip arm, not a boom. It is almost always used in conjunction with a 2-1/2" grip head, and its job is to position a gobo such as a flag, scrim, or silk, or another accessory, virtually anywhere between the light and the subject. If you need to hang a large softbox or a heavy strobe far out over a set, a proper boom with a counterweight system is the safer choice.

The arm's 40" length and 1.42 kg weight make it easy to handle, but the catalog does not confirm a maximum load capacity, so do not assume it can replace a boom for every fixture. Use it for offset flags, scrims, and small accessories where the hex pin and grip head can do their job, and keep the stand's base weighted.