Field Logic LLC — Patent Pending
One Cap. Three Functions. Zero Compromises.
TETHYRTM is the 3-in-1 conduit cap: it seals out debris, anchors your pull string or pull tape, and puts a precision layout mark at every stub-up. The TETHYR Thread Cap fits threaded fittings; the TETHYR Slip Cap fits PVC, RMC, or EMT conduit. 10 trade sizes, ¾" to 6".
🔒 Patent Pending · Designed for the Job Site · Built for the Trades
TETHYR™ Thread Cap — drag to rotate
Two configurations, three functions each. Debris protection, pull string anchor, and field layout center mark — built into every TETHYRTM Thread Cap and Slip Cap.
Seals the end of your conduit from concrete, mud, and construction dust throughout the rough-in phase. The Thread Cap threads into the fitting; the Slip Cap plugs directly into the open end of the conduit — both create a tight, reliable seal.
An internal cavity molded into the cap gives you a dedicated anchor point to tie off pull string or pull tape — secure, consistent, and always there when you need it.
The overhanging top lip covers the rim of the fitting or conduit end, keeping debris out of threads and open conduit ends alike so everything is clean and ready when it's time to pull.
The recessed cross slot on top isn't just for tool engagement — it gives you a precise, identifiable center point for tape measure, string line, or survey layout right from your conduit stub-up.
Available from ¾" through 6" in both configurations. Thread Cap sizes match standard NPT fitting specs (14 TPI down to 8 TPI). Slip Cap sizes match standard PVC and GRC conduit ID — exact to spec, every size.
Two configurations for every job. The TETHYR Thread Cap threads into threaded fittings. The TETHYR Slip Cap inserts into the bare end of PVC, RMC, or EMT conduit. Same three functions, same sizes — choose the fit your job calls for.
Every size delivers all three functions: debris seal, pull-string anchor, and field layout cross. Thread Cap (FLT) ¾" and 1" are in stock — larger sizes are sold out. Slip Cap (FLS) coming soon.
Installs on standard NPT threaded conduit fittings. ¾" through 6". ¾" (FLT75) and 1" (FLT100) are in stock — larger sizes are currently sold out.
| Size | Cat # |
|---|---|
| ¾" | FLT75 |
| 1" | FLT100 |
| 1¼" | FLT125Sold Out |
| 1½" | FLT150Sold Out |
| 2" | FLT200Sold Out |
| 2½" | FLT250Sold Out |
| 3" | FLT300Sold Out |
| 3½" | FLT350Sold Out |
| 4" | FLT400Sold Out |
| 6" | FLT600Sold Out |
⚠ For temporary use during construction only. TETHYR™ is not designed or intended for use in a completed or energized electrical installation. Not listed, labeled, or rated under any electrical product standard (UL, NEC, or equivalent). Remove before final inspection.
TETHYRTM Thread Cap (FLT) — ¾" and 1" in stock; larger sizes are sold out. Select quantities below. Free shipping on all orders. 25-unit minimum.
Need to share product details? Download the spec sheet (PDF)
Push-fit Slip Cap for PVC, RMC, and EMT conduit (FLS series) is in final production. For early availability or quote requests, contact us.
I've watched crews lose hours digging concrete out of conduit ends and rigging pull-string tie-offs that fail by the next shift. TETHYRTM exists because nobody had built the right cap — so we built it.
Field Logic LLC is an invention and technology company based in Washington State. We develop and commercialize tools and products that solve real problems in the trades.
We're not a big box brand. We're a small team that moves fast and stands behind what we ship.
Made in USA · Field Logic LLC · Patent Pending