Regular CAT 5 has a tendency to 1) deteriorate in uncontrolled environments, and 2) attract lightning. Outdoor CAT 5 deterirates much more slowly, and SUPPOSEDLY is safer lightning-wise.
This is more than shielded, though. Typical shielded CAT 5 has only one or two extra layers -- either just the foil layer, or sometimes foil with an electric insulator, such as mylar, between the conductor wires and the foil. This has mylar on both sides of the foil; two layers of exterior insulation; exterior insulatio is heavier gauge vinyl; possibly stronger conductor wires (subjective test); and some other stuff in there. According to the OEM manufacturer, it is suited for use as buried cable, or as outdoor "string" cable (i.e., doesn't need to be supported at frequent intervals).
Finally got it working. The basic trick is to cut off more of the outer insulator than the inner, and to "condition" the conductor wires by starting off with an inch and a half, pushing down the twists as close to the insulation exit as possible, and doing "practice runs" before each crimp at just over half an inch, half an inch, and finally the real thing at just under half an inch.
The two levels of cut leav enough of the inner insulator exposed to use inside the jack (under the wedge), while not having the outermost insulator, which is too wide to fit, get in the way.
The inch-and-a-half length leaves enough room to do a good job straightening out the twists, and leaves leverage to "pull the remaining twists down." The "practice" run ensures that there is enough wire length to make it all the way in spite of inevitable twisting and therefore shortening of some of the individual wires, and helps "condition" the wires to go exactly where they should, perfectly straight, when you cut it to barest tolerance.