It's a Small Form Factor power supply.
4.9 inches Wide, 2.5 inches Tall, and 3.9 inches Long.
Put's out a maximum of 150 watts, (Supposedly)
Has the following power cables;
A) (1) 20-pin ATX main power cable:
http://www.playtool.com/pages/psuconnectors/connectors.html#atxmain20The main power cable. Main power cable designs have moved up to the 24-pin design, with some main power cable connectors having a 20-pin connector, and a separate 4-pin connector
B) (1) 4-pin ATX +12 Volt power cable:
http://www.playtool.com/pages/psuconnectors/connectors.html#atx12v4This power cable is power for Intel Pentium 4 processors,and on up.
I have a eMachines T-1090 in my shop. (Still works great) It has a Pentium III 933MHz processor. Didn't know Pentium 4's were offered.
C) (4) 4-pin Peripheral power cables.
(The connector on the end of the power cable, is referred to as a standard 4-pin Molex connector. This is a misnomer. Molex was/is, a company that made this style of connector first. The name Molex was on the connector. The name stuck with people. It's just like referring to an open end adjustable wrench, as a Crescent Wrench)
http://www.playtool.com/pages/psuconnectors/connectors.html#peripheralD) (1) Floppy Drive power cable
Except for the size, and shape of this power supply, just about any low-end ATX power supply with a 4-pin +12 Volt power cable, would work.
More in additional comment.