Overview
The CablesOnline WP-C02MC-6 is a 6-pack of RJ45 female-to-female keystone jack couplers. It is not a tool for making cables; it is a part for joining two existing Ethernet cables, or for creating a junction point inside a keystone wall plate or patch panel. The listed specs are CAT5e / CAT6 / CAT6a compatibility, 250 MHz operating frequency, and up to 1 Gbps. Each unit weighs about 1.4 oz (40 g) and snaps into a standard keystone opening without tools.
The most practically useful feature is the multi-color pack. Six identical couplers become indistinguishable within a few months, so assigning a color per room or per purpose up front saves real time when you later have to trace a fault.
The Amazon.co.jp rating is 4.5 out of 5 stars (90% positive, captured May 2026), but it is based on only 5 reviews, so it should not be treated as evidence of quality.
Judge this product on its specs and your own use case.
Compatibility Guide
Both ports are RJ45 female, so you cannot plug a PC, router, switch, or access point directly into it. You always need a male-ended patch cable on each side. This is the single most common surprise after purchase. Keystone wall plates and patch panels are also sold separately and are not included here.
| Check | Detail | Where people get stuck |
|---|---|---|
| Connector | RJ45 female/female | No direct device connection; patch cables required |
| Category | CAT5e / CAT6 / CAT6a | Even CAT6a cable is limited by the 250 MHz rating |
| Frequency | 250 MHz | CAT6-class bandwidth; not aimed at 10GBASE-T |
| Speed | 1 Gbps | Fine for gigabit; treat 2.5G/10G as unsupported |
| Form factor | Keystone jack | Fits standard openings; plate not included |
| Quantity | 6 units (~40 g each) | Sized for color-coding, more than a one-off job needs |
One design caveat: each coupler adds two extra connection points. Ethernet's 100 m channel budget (commonly 90 m of horizontal run plus 10 m of patch cable) has less headroom as junctions accumulate.
On short home runs this rarely matters, but adding a coupler to a run that is already 60-70 m long can drop a link from 1 Gbps to 100 Mbps or make it unstable. For long extensions, pulling one correctly sized cable is more reliable than coupling two.
As for PoE, a passive coupler simply passes the contacts through and normally does not block power delivery. Still, confirm on the product page whether PoE support is stated.
With PoE+ or PoE++ current levels, poor contact quality can become a heat source.
Product Info
The specs are as listed above: RJ45 female/female connectors, CAT5e / CAT6 / CAT6a compatibility, 250 MHz, up to 1 Gbps, 6 units, roughly 1.4 oz (40 g) per unit. Nothing ships in the box except the six couplers - no manual, no wall plate. Since installation is a simple snap-in, the missing manual is not a practical problem.
Pricing deserves caution. As captured on 25 May 2026, the Amazon.co.jp listing showed ￥9,312; as captured on 1 June 2026, the eBay US listing showed $11.95 for the same 6-pack.
That is more than a fivefold gap. Import handling and shipping can create price differences on overseas accessories, but a gap this wide should not be read as a market rate.
Both figures are point-in-time snapshots and will move with sales and stock. Check the current price on the listing before buying, and compare against domestically stocked keystone couplers.
Best Use Cases
This suits people running a keystone-based home network who need to join cables behind a wall plate or patch panel. If you manage cabling by assigning a color per room or per floor, the multi-color 6-pack matches that workflow directly. It is equally practical in small offices where the cabling has to stay traceable after staff turnover.
It also helps when an in-wall cable is too short to reach and you do not own a crimping or punch-down tool. A coupler is one of the few ways to solve that without terminating anything.
If your network is entirely gigabit, you are unlikely to hit a performance limit.
Before You Buy
Start with price. Given the gap described above, ￥9,312 at the captured date is on the expensive side for six keystone couplers. Unless you are in a hurry, compare it against domestic keystone couplers - or against simply buying one CAT6a cable of the right length. The cost of six couplers often buys several multi-meter cables.
Next, who should skip it. If your network targets 10GBASE-T or 2.5GBASE-T, inserting a 250 MHz / 1 Gbps part into the path is not advisable.
Whether it works depends on distance and cable quality, which makes it the most annoying class of fault to diagnose. The same applies to already-long runs and paths near noise sources such as power cabling or inverter equipment.
For uses where dropouts are unacceptable, avoid adding junctions to permanent cabling.
A frequent misconception is that a coupler alone connects devices. It does not: you need two male patch cables.
Likewise, keystone plates and patch panels are not included, so confirm you have somewhere to snap the coupler into. For in-wall installs, check box depth and cable bend radius - forcing a tight bend degrades performance even on otherwise compliant cabling.
Finally, listing accuracy. With imported accessories, Amazon listing details (manufacturer, model number, quantity, color) sometimes disagree with the physical item.
With only 5 reviews, you cannot rely on other buyers to surface a mismatch. Confirm from the product image and title that you are ordering six female-to-female keystone couplers, and check quantity and shape again on arrival.
How It Compares
If you need to extend by more than a couple of meters, one correctly sized cable beats a coupler plus an existing cable, because it removes junctions. Domestic CAT6a cables with break-resistant latches come in convenient 1 m / 2 m / 5 m increments and hold up better where plugs are frequently swapped. Conversely, inside a wall or a junction box where nothing will be touched again, a coupler is the tidier answer.
The deciding question is whether that junction will ever be unplugged again. If yes, run a new cable; if no, use a coupler.
If 10G is on your roadmap, standardize the path on CAT6a or better and design the junction out entirely.
FAQ
Q. Can this connect my PC to a router by itself?
A. No. Both ports are female, so you need male patch cables on both sides.
Q. Will it do 10 Gbps?
A. It is rated 250 MHz / 1 Gbps. Do not assume 10GBASE-T support; for 10G, avoid junctions entirely.
Q. Is a wall plate included?
A. No. Only the six couplers are included; plates and patch panels must be bought separately.
Q. Does adding a coupler slow the link down? A.
On short home runs you will not notice. On paths near the 100 m guideline, extra junctions can destabilize the link.
Q. Does PoE pass through? A.
A passive coupler normally does not block power, but confirm the stated support on the listing. Contact quality matters at PoE+ and above.
Q. Why do prices differ so much between stores? A.
The captured figures were ￥9,312 on Amazon and $11.95 on eBay.
Import and shipping handling may explain part of it; always check the current price first.
Product Disclosure (Amazon)
- Manufacturer: CablesOnline
- Seller: Ｂ＆Ｂストア
- Fulfilled by: Ｂ＆Ｂストア
- ASIN: B00XWP36ZG
- Note: This article covers a manufacturer-made product based on Amazon listing details.
