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Quick answer: Most massage guns ship with 4–6 heads and you will realistically use two of them. The ball is your default for large muscle groups; the flat head handles denser muscle and areas near bone; the bullet/cone is for pinpointing knots; the fork/U straddles the spine and Achilles; the cushion is for tender or bony spots. The more useful question, and the one almost no product listing answers, is whether a replacement set will actually fit your device — covered below.
The attachment comparison
| Head | Best for | Who it suits | Avoid on |
|---|---|---|---|
| Ball / round | Quads, glutes, hamstrings, lats, calves | Everyone — the 90% head | Nothing much; it is the safe default |
| Flat | Denser muscle, areas close to bone, general use | Anyone who finds the ball too intense | Deep trigger points — too diffuse |
| Bullet / cone | Knots, trigger points, feet, forearms | People chasing one stubborn spot | Shins, spine, any bony surface, joints |
| Fork / U-shape | Either side of the spine, Achilles, calf seam | Desk workers with neck and upper-back tightness | Directly on the spine or tendon itself |
| Cushion / soft | Tender areas, bonier spots, post-injury caution | Beginners and anyone very sore | Deep work — it will feel like nothing |
| Thumb | Mimics a thumb press — lower back, trigger points | People used to hands-on massage | Bone, and anywhere sharply painful |
Will they fit? The compatibility question
This is the question the PAA boxes ask and the product listings dodge, so here is the honest answer: massage gun attachments are not universally interchangeable.
Most non-Theragun devices use a straight push-in shaft, and replacement sets are commonly sold as fitting a stated shaft diameter — 16 mm and 19 mm are the two figures you will see most often. Therabody’s Theragun range uses its own attachment system, which is why you will find sets sold specifically as “compatible with Theragun” rather than as generic kits.
How to check yours in thirty seconds: pull off an existing head and measure the shaft it was sitting on. Match that figure to the listing. If a listing does not state a shaft diameter or a named compatible device, treat that as a reason to skip it — a set that does not fit is the single most common complaint in attachment reviews.
Two more things worth checking before you buy a replacement set: whether the heads are solid or hollow (hollow heads deform under load and transmit less force), and whether the set includes a case, since loose heads disappear.
Measure it yourself — 30 seconds, and it settles the question
Brands do not consistently publish shaft diameter, and third-party listings guess at it constantly. Rather than trust a compatibility chart you cannot verify, measure the one on your own device:
- Pull off an attachment that came with the gun and look at the post that plugs into the head.
- Measure the post’s diameter with a caliper, or lay it against a ruler. The two common sizes in this category are 16 mm and 19 mm, and the difference is obvious once you have a number.
- Check whether the post is round or splined. A smooth round post usually accepts generic heads of the matching diameter. A splined, keyed or notched post is proprietary — Therabody’s devices are the best-known example — and generic heads will not seat properly no matter what a listing claims.
- Check the depth of the socket too. A head with the right diameter but a shallower socket will wobble under load, which you will feel immediately.
If a replacement set does not state a diameter at all, that is your answer about how carefully it was made. Write your number on a bit of tape inside the case; you will need it again.
Which head to actually start with
Use the ball for almost everything. Add the flat head when the ball feels too pointed. Reach for the bullet only when you are chasing a specific knot, and keep it off bone and joints. Most people never need the other three, which is worth knowing before you buy a 13-piece set to solve a two-piece problem.
When not to use an attachment at all
- Directly over bone or a joint — no head is designed for this.
- On a fresh injury, swelling, or a bruise — percussion is not appropriate for acute injury.
- On the front or sides of the neck — stay on the muscle at the back only.
- Anywhere sharply painful rather than dull-tender. Sharp pain is a stop signal, not a target.
- Over varicose veins, numb areas, or if you have a clotting disorder or are pregnant — check with a clinician first.
General wellness information, not medical advice.
Buying replacement attachments
If your device is a standard-shaft model, a generic multi-head set is inexpensive and worth having — mainly to replace the head you will inevitably lose. If you own a Theragun, buy Therabody’s own heads or a set explicitly listing Theragun compatibility.
Browse 16 mm attachment sets on Amazon →
Browse 19 mm attachment sets on Amazon →
Browse Theragun-compatible attachments on Amazon →
Check your shaft diameter before ordering. We link to searches rather than a single set because fit depends on your device, and the right answer genuinely differs person to person.
As an Amazon Associate we earn from qualifying purchases, at no extra cost to you. Links do not change what we recommend. Full affiliate disclosure.
Still choosing a device?
Attachments only matter once you have a gun worth attaching them to. See the five massage guns we compared, or the complete massage gun guide.
Free
The attachment fitment worksheet — the measuring method above as a one-page printable, plus a head-to-body-part chart you can keep in the case.
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Related reading
- Do compression boots actually work? — the other recovery device where the evidence is narrower than the marketing
- Using a massage gun for DOMS
- Massage gun for lower back pain
- Neck and shoulders
- How long to use a massage gun
Want the routines written out? The 28-Day Recovery Reset includes printable massage gun routines by muscle group.
FAQ
Are massage gun attachments universal?
No. Most non-Theragun devices use a straight push-in shaft, commonly 16 mm or 19 mm, and sets are sold to fit a stated diameter. Therabody’s Theragun range uses its own system, so it needs Theragun-specific heads. Measure your shaft before ordering.
Which massage gun head is best for knots?
The bullet or cone head concentrates force into a small area, which is what a trigger point needs. Use light pressure, keep it moving, and keep it off bone.
Which attachment should I use on my lower back?
The flat or thumb head on the muscle either side of the spine — never directly on the spine itself. The fork head can straddle it if you are confident about placement.
Do I need all the attachments that came with my gun?
Almost certainly not. Most people use the ball for nearly everything and occasionally the flat or bullet. A large multi-head set is mostly useful as spares.
What areas should I avoid with a massage gun?
Bone, joints, the front and sides of the neck, fresh injuries, swelling, and anywhere the pain is sharp rather than dull. If you have a clotting disorder, varicose veins, numbness, or are pregnant, speak to a clinician first.