Based on this product's specifications, here are some alternatives and similar models
Optical Fiber Attenuator CBO SFA23BK15 singlemode, fixed 15 dB
Summary description:
CBO SFA23BK15 is a singlemode optical fiber attenuator with a fixed attenuation of 15 dB. Designed for inline use in fiber optic links, it reduces signal power to prevent receiver overload and to balance channel levels. Suitable for testing, installation and maintenance of singlemode networks where controlled optical attenuation is required.