Passive or Active Cooling?
Preview text: Start with heat load and airflow.

Using this email in an article? Credit: HeatsinkUSA email via They Sent It, with a link to this page. Full-size image
- Subject
- Passive or Active Cooling?
- Preview text
- Start with heat load and airflow.
- From
- newsletter@
heatsinkusa.com - Brand
- HeatsinkUSA
- ESP
- Klaviyo
- Sent
- Wed Sep 23, 2026, 4:15 PM ET
- Size
- 44 KB
- Images
- 7
- Links
- 16, 3 of them buttons
- Subject length
- 26 characters
Against HeatsinkUSA's usual
Sent in the 4 PM hour, which holds 10% of its emails; 19% arrive in the 1 PM hour. The subject is 26 characters; its average is 33.
Email headers
What the brand's servers put on this email. Our receiving servers, the address we subscribed with and unsubscribe links are left out.
- From
- HeatsinkUSA <[email protected]>
- Subject
- Passive or Active Cooling?
- Date
- Wed, 23 Sep 2026 20:15:12 +0000 (UTC)
- Message-ID domain
- geopod-ismtpd-24
- Return-Path domain
- send.heatsinkusa.com
- DKIM signature
- d=heatsinkusa.com s=kl2
- List-Unsubscribe
- Present, one-click
Servers it passed through, newest first
- by recvd-…-8l9wv with SMTP
- from (unnamed) by geopod-ismtpd-24 with HTTP
Other sending headers (names only): X-Kmail-Account, X-Kmail-Message, X-Kmail-Ops, X-Report-Abuse, X-SG-EID, X-SG-ID, X-Entity-ID
Sent just before and after
| Oct 15, 2026 2:30 PM | Heatsinks for Your Next Audio Build | |
| Oct 7, 2026 11:45 AM | Heatsinks for Your Next Audio Build | |
| Oct 1, 2026 12:45 PM | Passive or Active Cooling? | |
| Sep 23, 2026 4:15 PM | Passive or Active Cooling? (this email) | |
| Sep 17, 2026 1:45 PM | Prototype Profiles Without the Bulk | |
| Sep 7, 2026 9:33 AM | Here’s to the People Who Build · Resent | |
| Sep 4, 2026 3:15 PM | Here’s to the People Who Build |
More from HeatsinkUSA
All HeatsinkUSA emailsOct 23, 2026 6:03 AM
Oct 19, 2026 6:06 AM
Oct 16, 2026 3:03 AM
Thinking About This Heatsink, Friend? 👀
Oct 15, 2026 7:14 PM
Heatsinks for Your Next Audio Build
Oct 15, 2026 2:30 PM
Heatsinks for Your Next Audio Build
Oct 7, 2026 11:45 AM
Oct 1, 2026 12:45 PM
Prototype Profiles Without the Bulk
Sep 17, 2026 1:45 PM







