UL Listed 12V 0.75A AC/DC Adapter Compatible with Motorola Cable Modem SB5100 SB5120 SB5101 SB5101U MT20-21120-A00F 503913-004 MT20-21120-A04F 503913-007 DTA100 DTA199 DCT700 12.0V 750mA Power Supply

Exactly what I needed!!!!!!!!!!!!Fits like the old one and seems to be made better at the junction where the wire goes into the connector pin.Has a re-enforced flexible portion at the base of the plug that helps support the wires inside, so they do not break or clack.The old one seemed to eventually break inside so you had to force a connection for electrical power to power the modem.It had to be pushed tight and would not always hold.This new one seems to be reinforced at that critical junction and flexes some so the thin wires inside will not be bent at a right angle.They may not break or crack as a result.Delicate wires inside.

I purchased this for my Motorola Surfboard 5101U modem (a compatible modem listed with this product). I plugged this into a standard wall outlet and it made a very loud pop noise and started smoking, producing the smell of burnt plastic, and blew up in my hand as I plugged it in. This is a faulty product. It's cheaply made. Please please please do NOT buy one of these! The price is very economical but compare that to your life or the cost of the house that you're living in. It's just not worth it! I've already contacted Amazon (which, by the way has excellent customer service) and they are trying to contact the seller. I just can't stress enough how DANGEROUS this product is!!! Also, it's not even the same as what's pictured!

Other than spending time sifting thru "next day delivery" & paying slightly more for such shipping, which was a let down, the product works as intended.

Power supply works. Fast delivery of product and at a reasonable price

Didn't work for the SB5120 modem, as promised. It worked for my backup modem which is an SB5101U, however. When I plugged it into the SB5120, it made a constant whirring noise and would not power on the modem. Returning and not ordering this product again.

Worked well.

Bought this for my laptop but found out it wasn't the power cord that was broken. It worked as expected

I ordered this adapter when I misplaced the original after doing a cross-country move. I was SO relieved to find a replacement adapter instead of having to purchase a brand new modem. Anyways, it fits my Motorola Surfboard modem SB5101U perfectly! I've had it for a week now, and there haven't been any issues. Highly recommend this product.