A&D FX-120i vs FX-120iN vs FX-300i: Which FX-i Balance Do You Need?
A&D FX-120i vs FX-120iN vs FX-300i: all three read 0.001 g, the FX-120iN is the NTEP Class II version for selling by weight, and the FX-120i is on sale for $699.00 (regular $1,495.00), in stock.
Short answer: the A&D FX-120i and FX-120iN weigh exactly the same: 122 g x 0.001 g, about one-second stabilization, on the same Ø130 mm pan. The difference is legal for trade. The FX-120iN is the NTEP Class II version (certified division e = 0.01 g), so you can buy or sell by weight with it. The FX-300i is the same balance with more capacity: 320 g x 0.001 g. Choose the FX-120i for reloading and lab work up to 122 g, the FX-120iN when you charge by weight, and the FX-300i when your samples or containers run over 122 g.
The FX-i series is one of the best-selling balance lines we carry. Reloaders, jewelers, pharmacies, dispensaries and QC labs all buy them, and the model names confuse a lot of buyers: the “N” and the capacity number change what you can do with the balance. MNM Scales is an authorized A&D dealer and one of the largest scale distributors in the country, with over 30 years in business. Here is how the three compare, using A&D’s instruction manual and the NTEP Certificate of Conformance (CC 08-045).
FX-120i vs FX-120iN vs FX-300i: specifications
| Specification | FX-120i | FX-120iN | FX-300i |
|---|---|---|---|
| Capacity x readability | 122 g x 0.001 g | 122 g x 0.001 g | 320 g x 0.001 g |
| Legal for trade | General purpose | NTEP Class II, e = 0.01 g | General purpose |
| Repeatability / linearity | 0.001 g / ±0.002 g | 0.001 g / ±0.002 g | 0.001 g / ±0.002 g |
| Stabilization (FAST) | About 1 second | About 1 second | About 1 second |
| Sensor | Compact Super Hybrid Sensor | Compact Super Hybrid Sensor | Compact Super Hybrid Sensor |
| Pan | Ø130 mm | Ø130 mm | Ø130 mm |
| Breeze break | Included | Included | Included |
| Calibration | External: 100 g or 50 g | External, behind the seal (see below) | External: 300, 200, 100 or 50 g |
| Interface | RS-232C (USB optional) | RS-232C (USB optional) | RS-232C (USB optional) |
Sensitivity drift is ±2 ppm/°C (10 to 30 °C) on all three, and A&D recommends a 30-minute warm-up for accurate weighing.
What the “N” means: FX-120iN legal for trade
The FX-120iN is built on the same mechanism as the FX-120i, but it ships set up for legal-for-trade use in the US and Canada. According to A&D’s legal-for-trade addendum:
- NTEP Class II: 122 g capacity with a certified (verification) division of e = 0.01 g, under CC 08-045. Class II is the accuracy class used for precious metals, gems and other high-value goods. See our legal for trade jewelry scale guide for Class II picks up to 12 kg.
- Two trade display modes: e = 10d (the default) shows 0.001 g with the last digit marked as non-certified; e = d reads directly in 0.01 g. A Measurement Canada mode is built in too.
- Keys change for trade use: the ON:OFF key becomes ON:OFF/ZERO, and RE-ZERO becomes TARE.
- Calibration is sealed: calibration uses a switch behind a sealing plate, and A&D specifies that calibration and sealing be done by a weights and measures official or an authorized service agent.
- Trade units: grams, ounces, pounds, troy ounces, carats and pennyweight are listed on the CC.
If you sell by weight in Texas, the balance also has to be placed in service. MNM Scales’ TDA-licensed registered technicians can calibrate, seal, inspect and place your scale in service (see our RWM-780 guide and our NTEP guide).
FX-120i or FX-300i: how much capacity do you need?
Both read 0.001 g with the same repeatability, so capacity is the only real question. Remember that the container counts: a powder pan, weigh boat, vial or jewelry tray uses part of the range.
- Up to 122 g including the container: FX-120i. Rifle powder charges, bullets, small lab samples and gemstones fit easily.
- Over 122 g, or heavy containers: FX-300i. Glass beakers, larger trays and batch weighing up to 320 g.
- In between, for trade: the FX-200iN (220 g x 0.001 g, NTEP Class II, e = 0.01 g).
- Over 320 g: step up to a 0.01 g toploader such as the A&D GX-4002A or GF-3002A (see our GX-4000 and GF-3000 replacement guide).
Which one should you buy?
| If you… | Choose |
|---|---|
| Reload ammunition or run an AutoTrickler | FX-120i (or the newer FX-123, which reads in grains and comes with a 100 g weight from MNM Scales) |
| Sell gold, gems or other goods by weight, up to 122 g | FX-120iN (or the newer Fortis FX-123N, also NTEP approved) |
| Weigh lab or QC samples up to 320 g | FX-300i |
| Sell by weight up to 320 g | FX-323N, the replacement for the FX-300iN (see FX-300iN replacement guide) |
Reloaders: both the FX-120i and FX-300i work with the AutoTrickler V4. Our FX-120i AutoTrickler setup guide lists the exact settings, and our best reloading scale guide compares the FX-120i with the FX-123. Already own one? Our FX-120i manual, explained covers the keys, units, function table and data output.
Calibration and service
The FX-120i and FX-300i calibrate with an external weight; see our step-by-step FX-120i calibration guide and our calibration weights, including the A&D 100 g weight (sold separately, not included with the FX-120i). Prefer a balance that calibrates itself? See internal vs external calibration balances. For the FX-120iN, calibration and sealing belong to an authorized service agent, which our registered technicians can handle. Send any of these balances to us for calibration with a certificate; mail-in turnaround is usually 1 to 3 business days:
FX-120i, FX-120iN, FX-300i and other balances up to 2.2 kg:
In-house calibration + certificate ($95) NIST calibration + NIST-traceable certificate ($395)
Frequently asked questions
What is the difference between the A&D FX-120i and FX-120iN?
They weigh the same, 122 g x 0.001 g with about one-second stabilization. The FX-120iN is the NTEP Class II legal-for-trade version with a certified division of e = 0.01 g, trade display modes, a TARE key and sealed calibration. Choose the FX-120iN if you buy or sell by weight.
Is the FX-120iN accurate to 0.001 g?
It displays 0.001 g and has the same 0.001 g repeatability as the FX-120i. For trade, the certified division is e = 0.01 g. In the default e = 10d mode the last digit is marked as non-certified, or you can choose e = d to read directly in 0.01 g.
Should I get the FX-120i or FX-300i?
Both read 0.001 g with the same repeatability. Choose the FX-120i if your sample plus container stays under 122 g, and the FX-300i for up to 320 g.
Can I calibrate an FX-120iN myself?
Calibration on the FX-120iN uses a switch behind a sealing plate, and A&D specifies that calibration and sealing be done by a weights and measures official or an authorized service agent. Our TDA-licensed registered technicians can calibrate and seal it.
Do the FX-120i and FX-300i work with an AutoTrickler?
Yes. Both are FX-i balances that work with the AutoTrickler V4. See our FX-120i AutoTrickler setup guide for the exact scale settings.
What calibration weight does the FX-120i use?
The FX-120i calibrates with a 100 g or 50 g external weight. The FX-300i accepts 300, 200, 100 or 50 g.