This is a Civil War knapsack which is painted on the front with the initials J.M. and Co. G, 4th N.J.M. for the 4th New Jersey Militia.
Following is an article on the 4th NJM with further information on each company.
http://www.firstbullrun.co.uk/NEV/Fourth%20Division/4th-new-jersey-state-militia.html
Company G, known as the Camden Zouaves, was accepted into state service for three months in Camden, Camden County, New Jersey, on April 17, 1861. It was mustered into United States service for the same duration at the State House, located at State and Delaware Streets in Trenton, Mercer County, New Jersey by Brevet Major & Captain T.T.S. Laidly of the United States Ordnance Department, and First Lieutenant A.T.A. Torbert of Company D, 5th United States Infantry, on April 27, 1861.
The knapsack is missing its straps and is meant for display to show off the beautiful paint job. Please review all photos. There is certainly further research to be done on this and it could possibly be identified.
Condition: II-