Loclen Electa Fountain Pen
Introducing the Loclen Electa. The short cap is threaded, with matching threads at both ends so it can be posted securely when writing; which makes it the perfect EDC or every day carry pen. Windows cut into the barrel let you see the ink inside. Cut-away sections at the top give you access to knurled brass inside, used to fill the pen with ink.

The knurled brass ring inside is attached to the piston knob on the end of the converter, and the converter screws into the nib section so everything is held in place firmly. You operate the piston using the knurled brass ring, without needing to open the barrel, so it acts just like a piston filler. The converter is a firm push-fit, mounted on three o-rings. LOCLEN says it adds a little bit of dampening, making for a smoother writing experience - like giving the nib some firm sporty suspension.