Britney Spears' Prop Knife Post Saves Knife Shop from Financial Ruin

The prop shop where Britney Spears claims she rented her famous dancin’ knives is seeing a big boost in sales after the shout-out … and it’s helped pull the store out of a financial hole.

The manager of Hand Prop Room in L.A. tells TMZ … online traffic and calls to the shop have doubled since Brit name-dropped their spot Thursday on Instagram. Rental sales for their props, especially knives, have gone up 50%.

We’re told everyone in the sales department has been getting calls from people asking about the singer and her knives — the manager has been fielding tons of calls about Britney.

The manager says Britney is partially to thank for saving the store … the place has been struggling during the writers’ and actors’ strikes this year.

The entertainment industry is the shop’s bread and butter, but no work meant fewer rentals … leading to a big financial struggle.

He says the store’s been bumping her songs nonstop ever since her post — so the promotion goes both ways!

As we reported, Britney shared her alarming dance video Monday, swinging and clanking the blades around with a caption that read, “Don’t worry they are NOT real knives !!! Halloween is soon.”