Accessory · 2000–2024 Meade Instruments Series 4000 3x Barlow 1.25" Meade Instruments · Series 4000 3x Barlow 1.25" Key specifications Accessory typeBarlow About Series 4000 3x Barlow lens (1.25"): a multi-coated achromatic power multiplier that increases the magnification of any eyepiece by 3x.