Each RETRAKT is ready to accept the Pilot G2 refill, just use the provided spring, and you're ready to go. If you want to run a Parker compatible refill instead, just drop the provided machined spacer into the upper half of the barrel (the part with the clip) and assemble as usual. Now you can easily find a refill at any office supply store if you run out of your favorite ink and can't wait.
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