Community price on backpack.tf: 11.0 keys, last changed 2019-10-16 (7.0y ago). The live quote above, 10.7 keys, is 3% lower and last moved 12d ago. They are different measures: the quote is what traders and bots are asking and bidding on the classifieds right now, and it moves for thousands of items every day; the community price is a suggestion accepted by vote, which changes only when someone argues it should. A quote well away from the vote is usually a price that is about to be re-argued. Community prices from backpack.tf, read under an hour ago.
Steam Market asking price: $33.76 — the lowest of one listing for the Massed Flies effect when we looked on 2026-10-07 01:43 UTC (6d ago). This is what a seller is asking, not what anything sold for. Steam pays out in Steam wallet funds, not cash, and Valve takes roughly 15% at the till — so asking prices there run well above the 10 keys, 41.88 ref shown above, which comes from the keys-and-metal market on backpack.tf. The two are different markets and are never blended. Steam lists the item as “Unusual Brain Interface”, with no effect in the name — the effect comes from the individual listing.
Price history
139 observations
Interactive chart. Press the left and right arrow keys to move along the series, Home or End to jump to either end, Escape to clear.
The key axis converts at today's rate. Prices are recorded in metal, so a line that is flat in keys followed the key rate rather than standing still.
Massed Flies Brain Interface sell price, 2025-09-25 to 2026-10-13: 139 observations, from 12.1 keys to 10.9 keys. Sampled evenly across the range.
Observed (UTC)
Sell
Buy
25 SEP 2025 · 03:29 UTC
12.1 keys
9.85 keys
25 OCT 2025 · 18:08 UTC
9.61 keys
8.68 keys
5 APR 2026 · 18:30 UTC
11.3 keys
6.53 keys
29 JUN 2026 · 01:14 UTC
10.2 keys
8.89 keys
17 JUL 2026 · 16:44 UTC
9.66 keys
8.36 keys
20 AUG 2026 · 16:09 UTC
10.7 keys
9.29 keys
23 AUG 2026 · 06:09 UTC
10.3 keys
8.95 keys
25 AUG 2026 · 06:09 UTC
10.6 keys
9.25 keys
25 AUG 2026 · 18:10 UTC
10.9 keys
9.46 keys
27 AUG 2026 · 16:09 UTC
10.7 keys
9.31 keys
31 AUG 2026 · 06:09 UTC
10.4 keys
9.08 keys
1 SEP 2026 · 22:08 UTC
10.4 keys
9.06 keys
2 SEP 2026 · 10:08 UTC
10.4 keys
9.03 keys
3 SEP 2026 · 00:08 UTC
10.4 keys
9.02 keys
4 SEP 2026 · 18:08 UTC
10.2 keys
8.86 keys
5 SEP 2026 · 06:08 UTC
10.4 keys
9.00 keys
8 SEP 2026 · 16:09 UTC
9.84 keys
8.56 keys
11 SEP 2026 · 12:09 UTC
9.72 keys
8.44 keys
15 SEP 2026 · 08:10 UTC
10.0 keys
8.73 keys
17 SEP 2026 · 04:09 UTC
10.2 keys
8.86 keys
21 SEP 2026 · 04:09 UTC
9.84 keys
8.55 keys
22 SEP 2026 · 02:09 UTC
10.3 keys
8.92 keys
22 SEP 2026 · 10:08 UTC
10.7 keys
9.27 keys
23 SEP 2026 · 12:07 UTC
9.97 keys
8.66 keys
25 SEP 2026 · 16:08 UTC
10.7 keys
9.34 keys
28 SEP 2026 · 10:08 UTC
10.2 keys
8.88 keys
29 SEP 2026 · 04:08 UTC
10.7 keys
9.31 keys
29 SEP 2026 · 16:11 UTC
11.0 keys
9.53 keys
30 SEP 2026 · 06:08 UTC
10.5 keys
9.08 keys
30 SEP 2026 · 20:09 UTC
10.1 keys
8.78 keys
1 OCT 2026 · 04:09 UTC
10.7 keys
9.27 keys
5 OCT 2026 · 17:09 UTC
10.6 keys
9.25 keys
6 OCT 2026 · 07:09 UTC
10.8 keys
9.36 keys
8 OCT 2026 · 11:09 UTC
10.8 keys
9.40 keys
8 OCT 2026 · 17:10 UTC
10.5 keys
9.15 keys
9 OCT 2026 · 07:09 UTC
10.8 keys
9.36 keys
10 OCT 2026 · 15:10 UTC
10.7 keys
9.28 keys
12 OCT 2026 · 05:09 UTC
10.6 keys
9.26 keys
12 OCT 2026 · 11:08 UTC
10.8 keys
9.40 keys
13 OCT 2026 · 03:08 UTC
10.9 keys
9.45 keys
Price history in numbers
139 readings since 25 Sep 2025
Over the last 30 days the Massed Flies Brain Interface's sell price ranged from 9.27 keys to 11.0 keys and is up 11.8% after 75 moves. Over a year it ranged from 6.94 keys to 11.8 keys (up 7.7%). Today's 10.9 keys sits in the upper third of its range: the lowest we have recorded is 6.94 keys (11 Jul 2026) and the highest 12.1 keys (25 Sep 2025). The price has moved 138 times since we began recording it — about once every 3 days.
Mann-Bird of Aberdeen