Since Motley Fool co-founder Tom Gardner recommended Mine Safety (NYSE:MSA) in Hidden Gems a year ago, the stock has soared almost 150%. Don't let the name fool you. From its mining industry roots has emerged a very strong safety-products company.

For example, management just announced its consumer safety products will go on sale at 6,200 True Value hardware stores starting in the fourth quarter. For the do-it-yourselfer looking for higher quality eye, ear, head, and/or respiratory protection -- or just an excellent first aid kit -- Mine Safety will be there to serve.

Look at last quarter's earnings. The 21% increase in net sales and 49% increase in net income was driven by strong military, homeland security, and fire services sales. No mining industry there, right? Well, not exactly.

Mine Safety has made industrial (and mining) gas masks and helmets for years. Now it makes gas masks and Advanced Combat Helmets for the military, too.

When the National Fire Protection Association and the National Institute of Occupational Safety and Health issued new breathing-apparatus performance standards for protection against chemical, biological, radiological, and nuclear agents (all industrial needs), Mine Safety was first to market with a product that met both standards -- and had strong homeland security sales as well.

When Tom Gardner recommended this company to his subscribers, there were no analysts following it, and institutional ownership was less than 15%. In a phrase, the company was undiscovered on Wall Street. Now there is 43.4% institutional ownership and four analysts watching -- after the stock has soared.

The heart of any good investment is rising sales, a promising outlook, and most importantly rising free cash flow. Couple that with little Wall Street interest, and you have a Hidden Gem. Let the company continue that success, and continue to be "discovered," and there may be more gains on the horizon.

Say "Happy Anniversary" to Tom Gardner for the Mine Safety recommendation he made one year ago today by trying a free trial to his Hidden Gems newsletter. His 15 selections have an average return of 27% vs. the S&P 500's 14%.

Fool contributor W.D. Crotty does not own stock in Mine Safety.

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