If you only single dose on your Baratza Virtuoso, you can swap out your large stock hopper for 3D printed our low-profile, single dose hopper designed specifically for the Virtuoso models. If you also have issues with retention, then say farewell to it with our optional bellows that will help you achieve up to an incredible 0.0g to 0.2g retention on each grind*. [Design Features] My design philosophy revolves around simplicity and utmost effectiveness, both meticulously woven into the design of our Baratza single dose hopper and bellows. Both Hopper Sizes: The single dose hopper replaces the original stock hopper while maintaining its tapered aesthetics. Simple installation, taking less than a minute and requiring no additional tools. Maintains the same interaction for adjusting entire grind size. Maintains the original range of grind size adjustment. Fits and works with the stock gasket seal above the burrs Optionally combo with our silicone bellows (which also perfectly fits the Niche Zero and Duo) for up to 0.0g to 0.2g* retention. Includes a 3D printed TPU gasket for extra bellows performance (On ESP, you can use stock gasket instead) Includes a 3D printed lid Compact Size: Approximately 40g capacity Built in anti-popcorn design reduces most popcorning (even better with bellows). Low profile design allows an approximate 7cm (2-3/4in) of clearance compared to the original full-sized stock hopper, and is even shorter than Baratza's single dose hopper. XL Size: Approximately 55g capacity Bean buffer chamber of ~24g capacity which allows bellows to be placed back on hopper immediately after dosing No built-in anti-popcorn cover, as bellows acts as the anti-popcorn cover Note: Some photos and videos shown are the product on the Baratza Encore, a different grinder, but they are fully cross compatible. [Compatibility] Hoppers in their respective "Group" will fit in all grinders listed under the same group. Group 1 Compact hoppers will fit on Group 2 grinders but will not be an optimal experience. Group 1 XL Hoppers will work fine on Group 2, but the 3D printed seam line will be facing the front. Group 2 Compact hoppers will only fit on Group 2 grinders, and may not fit on some Group 1 grinders like the Encore ESP. Group 2 XL hoppers will work fine on Group 1 grinders, but the 3D printed seam line will be aligned with the grind adjustment indicator. Group 1 Virtuoso Virtuoso+ Encore Encore ESP It is somewhat compatible with the following grinders, but it will not be an optimal experience due to the anti-popcorn design: Group 2 Vario+ Vario W+ Vario Vario-W Forte AP Forte BG (Optional silicone bellows is 100% cross-compatible with Niche Zero and Duo and other Introvert single dose hoppers) Not compatible with: Sette series Encore ESP Pro Subpar Bellows Option These bellows will have a pronounced distorted form, and possibly other surface blemishes, but they otherwise are fully functional. Although some of the openings of the bellows may look far from circular, they will conform when placed into the hopper. See an example of subpar here Adding Optional Bellows Later If you already own the hopper and would like to add the optional bellows, you can purchase it separately here: Silicone Bellows for INTROVERT Single Dose Hoppers [*Disclaimer] The finest grind range (0-20) may decrease bellows effectiveness due to restricted air flow. Adjust to a coarser range (20+) while pumping bellows to fully clear retention. Grinding after changing grind size may still cause some retention Using darker roasts may cause more retention RDT method not recommended Achieve the best results with lighter roasted beans and at a consistent grind size setting. Does not include the grinder nor the stock hoppers in the photos