The Delta Write Balance fountain pen is specially designed to offer optimal balance for the user that reduces fatigue and provides a more comfortable writing experience. The Write Balance pen features a removable two-gram weight, which can be added or removed depending on personal preference. With the weight inserted into the cone, the fountain pen's balance is shifted toward the back end, meaning that the user's hand is more involved in the writing. This top weighted center of gravity is often preferred by calligraphers.With the weight removed from the pen, the balance is weighted towards the nib. This is typically the most comfortable balance for every-day use. The pen fills via standard international ink cartridge or Delta's threaded converter for easy bottle filling.