Welcome to the Forum! Lots of .44 Magnum and Model 29 fans here, so you're in good company. You're fortunate to have a nice 5-screw .44 Magnum with its blue/black pebble grain leatherette case (should have a blue satin lining). Wiregrassguy and Doc44 have described the Sight Adjustment Tool (SAT) that you were asking about, and your case should also have a cleaning rod, brass brush, and cotton swab (mop). You didn't mention the barrel length of your .44 Magnum (4" or 6-1/2"), or the finish (blued or nickel). If you'd like more information about the manufacture date, etc., please include the s/n and a description...our Forum gurus (i.e. Doc44) have a wealth of information about these early revolvers. Photos are always appreciated, too. Enjoy!