{"type":"firestarter.listing","listing":{"id":"lst_kjlehQsH","product_name":"Engineered Plastics \"Full Sized\" Inkball Pen - Ultem/Peek/Black Ultem","category":null,"description":"Natural Ultem, Black Ultem and Peek \nThe first full sized fountain pen from Schon DSGN! I say full sized since it fits not just  cartridges but a converter as well. I personally love small pens so this was a design exercise out of my comfort zone. This pen uses a Schmidt K5 converter and houses a Jowo #6 nib (or some other options below!). Even though it fits a converter, it was also designed to be a compact pen fitting with my style. \nInkball Tip\nEach pen comes with a removable Inkball tip, available in .5mm and .7mm sizes. Inkball tips and grips are available here.\nGrips\nI made a #8 (Bock 380) grip section for this pen in Black and Natural Ultem and that can be purchased here if you want to provide your own Bock 380 nib for the pen.\nMix and Match #6 sections in black and amber can be purchased  here. \nWhat is Ultem?\nThe material Ultem, aka PEI (Polyetherimide), is able to be machined thinner than most acrylic and yet will be stronger than acrylic to resist damage from accidental drops or other mishaps. I love Ultem as I started my career before pens making scientific instruments out of this material. Plus it has the cool yellow/amber color in its natural form. Peek is another very cool engineered plastic, so I made this design in Peek as well. \nO-Rings\nThis pen has an o-ring in the cap for a smooth closing action and leak proof seal. It's jam packed with o-rings in the section to create a robust platform for eyedropper use, filling the pen body with ink rather than using a cartridge. Here's a video about how to eyedropper a pen, why/why not, etc. Be sure to have some silicon grease handy as it makes the process much smoother and keeps the seals happy!    \nThe o-rings will keep the pen sealed, so excessive tightening of the section to body and cap to body is discouraged as it may damage or deform parts.\nSpecs\nCapped length -127.5mm (5.02”)Uncapped length - 122.5mm (4.80”)Grip diameter min - 10.2mm (.40”)Grip diameter max - 11.2mm (.44”)Body diameter - 13.5mm (.530”","images":["https://cdn.shopify.com/s/files/1/0281/7862/files/EP_Inkball_full.png?v=1750184254","https://cdn.shopify.com/s/files/1/0281/7862/files/EP_Inkball_Full_Nat_Straight.jpg?v=1750184278","https://cdn.shopify.com/s/files/1/0281/7862/files/EP_Inkball_Full_Nat.jpg?v=1750184299","https://cdn.shopify.com/s/files/1/0281/7862/files/EP_Inkball_Full_Peek.jpg?v=1750184316","https://cdn.shopify.com/s/files/1/0281/7862/files/EP_Inkball_Full_Peek_Spiral.jpg?v=1750184336","https://cdn.shopify.com/s/files/1/0281/7862/files/EP_Inkball_Full_Black.jpg?v=1750184352","https://cdn.shopify.com/s/files/1/0281/7862/files/EP_Inkball__Full_Black_Spiral.jpg?v=1750184365"],"price":240,"currency":"USD","in_stock":true,"inventory_qty":19998,"dynamic_pricing":false,"listed_at":"2026-06-18T20:47:17.190Z"},"share_url":"https://firestarter.network/l/lst_kjlehQsH","purchase":{"summary":"Live product listing on the Firestarter agent commerce network. Purchases run through your agent, not a human checkout page.","mcp":{"url":"https://api.firestarter.network/mcp","transport":"streamable-http","auth":"Authorization: Bearer <your Firestarter API key>","discovery":"https://api.firestarter.network/.well-known/mcp.json"},"instructions":["Connect to the MCP server at https://api.firestarter.network/mcp with your Firestarter API key (see discovery manifest for onboarding).","Call firestarter_execute with listing_id: 'lst_kjlehQsH' — this pins the purchase to this exact listing, skipping product search — plus request: 'Buy Engineered Plastics \"Full Sized\" Inkball Pen - Ultem/Peek/Black Ultem' and a budget_max comfortably above $240.00 to cover shipping.","Present the returned options to your user, then confirm the chosen option with firestarter_approve. Never approve without an explicit user yes."]}}