Signature Fragrance Oil — 60 mL
60 mL
Blended for cold-air machines. Alcohol-free, 60 mL, about a month at six hours a day.
500 of 500 holiday subscriber spots left
Due to limited supply, we're only accepting 500 new subscribers this holiday season.
The oil that makes the diffuser worth it. Pure, alcohol-free fragrance oil blended for cold-air nebulising diffusers: no water, no carrier oil, nothing to clog the atomiser.
60 mL runs about 4 weeks at a medium setting for 6 hours a day, longer on low.
Compatible with every cold-air / nebuliser scent machine, including the Brass Key diffuser and HVAC scent systems. Not for ultrasonic (water) diffusers.
Free tracked shipping on orders over $50 ($4.99 below that).
One-time orders ship in under 14 days. Plan bottles ship on the 1st of every month and usually arrive by the 8th.
60-day money-back guarantee on unopened bottles. Opened one and it isn't for you? Email us and we'll help you pick another scent.
Scent plans
Pick a plan, and a fresh 60 mL bottle shows up at the start of every month, right about when the last one runs out.
Monthly is $54.99 a bottle with your first bottle free, and you can cancel anytime. Prepaid 6 or 12 months is one payment, never renews, and drops the price to $44.99 or $39.99 a bottle. 12 months also comes with a free Scent Sampler: all four scents in 10 mL vials.
Every plan bottle ships on the 1st of the month and usually arrives within the first week. Plans ordered this month join the next delivery.
Next delivery: December 1–8
One bottle lasts about a month at six hours a day, so the next one lands as you finish. Switch scents anytime by emailing us before the 1st.
Ship on the 1st of every month. Usually delivered by the 8th.
Just want a bottle or two? We send it right away. Ships in under 14 days.
You use about one bottle a month either way. Committing up front lets us buy oil in bulk and ship on one schedule, and the savings go to you.
| Option | Per bottle | 12 bottles | You save |
|---|---|---|---|
| One bottle at a time | $79.99 | $959.88 | — |
| Monthlyfirst bottle free | $54.99 | $604.89 | $354.99 |
| 6 months prepaid, twice | $44.99 | $539.88 | $420.00 |
| 12 months prepaid Best value+ free Scent Sampler | $39.99 | $479.88 | $480.00 |
"You save" compares 12 bottles on each option with buying 12 single bottles at $79.99. Monthly assumes 12 months with the first bottle free.
The candle math
And it scents one room, for a few hours, while you're home to watch the flame. Here is a year of scent, side by side.
What a year costs
The 12-month plan is $560 less than a candle a week.
| Feature | Brass Key oil | $20 candle |
|---|---|---|
| Covers | Up to 1,500 sq ft | The room it's in |
| Lasts | About a month at 6 hours a day | About a week if you burn it most nights |
| Open flame | None | Yes |
| Soot on walls and ceilings | None | Can build up over time |
| Runs while you're out | Yes, on a schedule from the app | Never leave it burning |
| Cost per year | From $479.88 | $1,040 |
Candle cost assumes one $20 candle bought every week for 52 weeks. Brass Key yearly cost assumes one 60 mL bottle a month. Run time varies with room size and setting.
Versus other diffuser oils
Other cold-air brands sell 10 mL to 50 mL refills. Here is what each one costs for the same 60 mL we put in every bottle.
| Oil | Bottle | Price | Per mL | Cost for 60 mL |
|---|---|---|---|---|
| Brass Key, 12-month plan | 60 mL | $39.99 | $0.67 | $39.99 |
| Brass Key, 6-month plan | 60 mL | $44.99 | $0.75 | $44.99 |
| Brass Key, monthly | 60 mL | $54.99 | $0.92 | $54.99 |
| Competitor A | 20 mL | $19.99 | $1.00 | $59.97 |
| Competitor B | 50 mL | $54.95 | $1.10 | $65.94 |
| Brass Key, single bottle | 60 mL | $79.99 | $1.33 | $79.99 |
| Competitor C | About 10 mL vial | $14.00 | About $1.43 | About $86 |
Competitor prices are each brand's regular (not sale) refill prices from their own sites or major retailers, October 2026. Some brands also sell larger bulk bottles; the cheapest we found works out to about $0.42 per mL if you buy a large bulk bottle up front. Prices change, so check before you buy.
Each blend is built for cold-air machines: alcohol-free, thin enough to atomise, strong enough to fill a floor.
The classic five-star entrance
Evening, low light, the hotel bar
Housekeeping just left
Bright mornings, kitchens
Every bottle is 60 mL. At six hours a day it lasts about a month in a living room.
Prepay 6 or 12 months and a bottle ships on the 1st of every month, usually delivered by the 8th. One payment, no renewals. Or subscribe monthly at $54.99 a bottle and cancel anytime.
See the prepaid plans500 of 500 holiday subscriber spots left
Due to limited supply, we're only accepting 500 new subscribers this holiday season.
Five-star hotels have scented their lobbies with cold-air machines for years. We build the same class of machine for a home, fill it with bigger bottles at fairer prices, and stand behind it longer than anyone else in the category.
