Ultrasonium lists 2 more people on its directory entry and Ultrasonium was listed 10 days earlier.
| Rank | Company | Score | Team size | Listed | Founders named | Tech signals |
|---|---|---|---|---|---|---|
| 1 | Ultrasoniumleads | 82 | 5 people · 83rd pctadds 35 | 2026-08-04 · 38d agoadds 18 | 4adds 25 | 2adds 4 |
| 2 | Mass Magnetics | 63 | 3 people · 57th pctadds 23 | 2026-08-14 · 28d agoadds 18 | 2adds 18 | 2adds 4 |
A score out of 100 comparing what each company's record shows for team size within its batch, listing recency, founders named and tech-stack signals.
- Team size within its batchup to 42
- Listing recencyup to 25
- Founders namedup to 25
- Tech-stack signalsup to 8
- 75 and up
- 55 to 74
- 35 to 54
- under 35
| Measure | Ultrasonium | Mass Magnetics |
|---|---|---|
| Batch | Summer 2026 | Summer 2026 |
| Team size | 5 | 3 |
| Stage | Early | Early |
| Status | Active | Active |
| Industry | Industrials | Industrials |
| Sectors | Hard Tech, Hardware, Robotics, Manufacturing | Hard Tech, Robotics, Drones, Manufacturing, Defense |
| Based | Boston | Boston |
| Year founded | 2026 | 2026 |
| Open roles | 0 | 0 |
| Founders | 4 | 2 |
| Group partner | Diana Hu | Vivian Midha Shen |
Ultrasonium
Against the 213 companies on file from Summer 2026. Median team 2, largest 30.
Mass Magnetics
Against the 213 companies on file from Summer 2026. Median team 2, largest 30.
Ultrasonium
Mass Magnetics
Read away from the record, per side. A side with nothing here is a side where nothing answered — the space is left empty rather than filled from the other one.
Ultrasonium
We make the world's most difficult metal parts faster, cheaper, and more versatile.
The title and description the site itself served, answering 200. Not a cached copy and not the company's directory entry — what was live when we asked.
Mass Magnetics
Secure, domestic, high-performance magnets, made fast and made in America. Rapid sintering from recycled feedstocks. DFARS 252.225-7052 compliant.
The title and description the site itself served, answering 200. Not a cached copy and not the company's directory entry — what was live when we asked.
The full profile
Source Check, INVEST, RECRUIT and Press Requests on Ultrasonium
- Source Check — verify what Jack Qiu states, against the registers that hold it.
- INVEST — take this comparison past the two, across the whole group.
- RECRUIT — see who is already on both teams.
- Press Requests — connect with Jack Qiu for a story.
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Watchlist UltrasoniumBoth profiles in full: Ultrasonium · Mass Magnetics.
Both sides are read from the Y Combinator directory — Ultrasonium and Mass Magnetics. Both sites were read directly on the date shown — Ultrasonium and Mass Magnetics.