Motorola SURFboard SB6121 (575186-001-00) 4x4 DOCSIS 3.0 Working Modem As Is WOW

Prime Effects
(1810)
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US $9.99
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Condition:
Used

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Shipping:
US $17.15 USPS Ground Advantage®.
Located in: Chicago, Illinois, United States
Delivery:
Estimated between Sat, Nov 22 and Fri, Nov 28 to 94104
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Seller does not accept returns.
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eBay item number:116350718900
Last updated on Nov 08, 2025 06:41:46 PSTView all revisionsView all revisions

Item specifics

Condition
Used: An item that has been used previously. The item may have some signs of cosmetic wear, but is ...
Country of Origin
China
Maximum Downstream Data Rate
172 Mbps
Maximum LAN Data Rate
172
Color
Black
Custom Bundle
No
Ports
Ethernet (RJ-45)
MPN
SB6121
Brand
Motorola
DOCSIS Standard
DOCSIS 3.0
Type
Cable
Modem Device Type
Cable Modems & Routers
Manufacturer Warranty
None
Model
SB6121
Connectivity
Single Ethernet (RJ-45) Port
Carrier
Comcast, Charter, Cox, Cablevision
Number of LAN Ports
1
Category

Item description from the seller

About this seller

Prime Effects

100% positive feedback•2.9K items sold

Joined Oct 2000
Welcome to my eBay store PRIME EFFECTS. I am committed to providing an eclectic assortment of merchandise to meet the needs of discriminating customers from around the world. Your business is deeply ...
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Detailed seller ratings

Average for the last 12 months
Accurate description
4.9
Reasonable shipping cost
4.7
Shipping speed
5.0
Communication
5.0

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Product ratings and reviews

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4.6
252 product ratings
  • 199 users rated this 5 out of 5 stars
  • 33 users rated this 4 out of 5 stars
  • 7 users rated this 3 out of 5 stars
  • 2 users rated this 2 out of 5 stars
  • 11 users rated this 1 out of 5 stars

Easy to set up

Good value

Performs well

Most relevant reviews

See all 126 reviews
  • by cranberryduff0
    Mar 08, 2016Top favorable review

    Compact size, Works fine

    This modem arrived in thin packaging, no padding, no box, but included all necessary parts and nothing was damaged. The plastic housing looks lightly scratched all over as if it had been cleaned with a gritty cloth. But it works perfectly and was incredibly easy to set up. I called Time Warner to activate it and within a few minutes I was all set to return the leased modem and recoup the cost of this used unit in three months. To save money I switched to the slowest internet plan and have no problems streaming Netflix with the 1.5 mbps plan (note the decimal - that's one-and-a-half mbps, not fifteen) - For older people living alone on a limited income, buying a cheap used modem like this is a good investment.

    Verified purchase: YesCondition: Pre-OwnedSold by: surpluscablesupplys

  • by darthanianmaul
    Apr 21, 2016Top critical review

    Modem sucks and you might have to buy 2 or 3 a year

    Necessary evil!. I bought my own modem so I don't have to pay Comcast $10 a month. This is my 3rd modem. Even if you buy brand new these keep breaking down. This is a scam that is a partnership with Motorla, Aris and the providers.

    Verified purchase: YesCondition: NewSold by: twintwist

  • by romanstypula
    Sep 15, 2015

    Had to call Comcast to activate but it works great. Only issue was that power supply fell apart during shipping; 12V 1 Amp is generic enough. Happy.

    The product is perfect for getting saving some green from Comcast rental fees. It will be many years before they roll-out DOCSIS 3.1, make it affordable enough after they do and available. So in the mean time, save money on your monthly bill. This one works great for the 50mb ish speeds.

    Verified purchase: YesCondition: Pre-OwnedSold by: xiayuanhuan

  • by ethelred_the_unready
    May 10, 2017

    If is what it is, and it does what it does.

    The Motorola SB6121 is a reasonably small DOCSIS 3.0 cable modem. It can handle data rates up to a nominal 200Mb/s (actual 195Mb/s), and can work with most cable providers (check compatibility before buying). This model does not incorporate a router. Setup is simple - connect the cable cord, the Ethernet cord, and power and you're away. Setup with the cable company was simple - one phone call, read one number, and the new modem was working. One irritation with a cable modem (as opposed to a modem-router) is that if you connect a different computer/router/etc, you have to power cycle the modem. All in all, this has been a great deal for me, eliminating the modem rental and other fees . Now I just have to see if it lasts.

    Verified purchase: YesCondition: Pre-OwnedSold by: speedy-ship

  • by diamond33156
    Nov 07, 2015

    Very easy to use

    The product is plug and play. Only thing to do is call Comcast and tell the numbers that are on the back of the modem. They asked me if I will be using a router to have it ready as well. So I connected during the process that took less tan a minute and it is working perfect. I was looking to the perfect match and most of the people recommended to use a router Netgear WNDR3700 that is very reliable and I can confirm this as well.

    Verified purchase: YesCondition: Pre-OwnedSold by: crossedarrowscommemoratives

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