MasterCool's web site lists various tools for the various sizes. You might want to check the size of your schrader valve and purchase the appropriate tool.

As I said earlier, mine was R12 and required a different tool.

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1986 300E (3/2002) Rear ended and totaled (10/2009)
2000 Xterra (5/2000)
1992 400E (11/2009) -Sold
1986 300E (12/2009) - Sold
2004 E500 Wagon (6/2013) - Sold