(Reuters) -Britain's Spectris ( SEPJF ) said on Friday it has rejected a second takeover proposal from private equity firm KKR, days after the scientific instruments maker backed a possible competing $5 billion bid from Advent.

Spectris ( SEPJF ) did not provide details on KKR's proposal, noting only that it was the second proposal by the PE firm it had rejected.

The company, which provides hardware and software solutions to sectors such as pharmaceuticals, steel and automotive, said on Monday it would accept private equity firm Advent's proposal of 37.63 pounds per share if a formal offer was made.

Advent and KKR did not immediately respond to Reuters' requests for comment. The competing proposal by KKR was first reported by the Wall Street Journal on Friday.

Spectris ( SEPJF ) is the largest takeover target this year in Britain, a country that has attracted overseas buyers in recent years due to relatively cheap valuations.

Under UK takeover rules, KKR has until July 11 to make a formal offer or walk away.