Think about it: 70% more black ink in this refill. Great in Multi-Pens - you use black probably way more than the red and blue colors -right? The tube is thinner and uses 30% less plastic and comes in paper packaging which is good for the environment as well.
Oil-Based ballpoint pen refill fits wherever an SXR-80 or an SXR-204 will fit (0.5 / 0.7).